Climaax M6 deliverable Updating Västernorrland's Climate Risk and vulnerability Assessment using the CLIMAAX methodology

County administrative board of Västernorrland Climate and vulnerability analysis for Västernorrland County Using the CLIMAAX Methodology Nr.: 109 60 66 Revision: 3 Date: 2025-08-14 Climate and vulnerability analysis for Västernorrland County Using the CLIMAAX Methodology Nr.: 109 60 66 Revision: 3 2025-08-14 | Sida 2 av 23 109 60 66 Climate and vulnerability analysis Client: County administrative board of Västernorrland Client contact person: Felicia Edholm Consultant: Norconsult Sverige AB Project manager: Anders Rimne Case officer: Daniel Öman This document has been prepared by Norconsult as part of the assignment to which the document pertains. The copyright belongs to Norconsult. The client has, unless otherwise agreed, only the right to use and copy the reported assignment results for the intended purpose of the assignment. Revision Date Description Prepared Reviewed Approved 1 2025-06-27 Version for internal review Daniel Öman Anders Modig Anders Rimne 2 2025-07-04 Version for external review Daniel Öman Anders Rimne 3 2025-08-14 Revised after external review Anders Rimne Climate and vulnerability analysis for Västernorrland County Using the CLIMAAX Methodology Nr.: 109 60 66 Revision: 3 2025-08-14 | Sida 3 av 23 109 60 66 Climate and vulnerability analysis Summary The County Administrative Board of Västernorrland has received approved support from the EU-funded CLIMAAX project to conduct a climate and vulnerability analysis. CLIMAAX is an EU-funded project within the framework of the EU's Mission on Adaptation to Climate Change. The CLIMAAX project aims to strengthen Europe's ability to adapt to climate change, especially in regions that are particularly vulnerable and have limited resources for adaptation. The purpose of the project is to contribute to the harmonization and consolidation of the practice of climate risk assessment. The purpose of this report is to briefly present the climate-related risks identified from the CLIMAAX analysis, how these relate to previous experiences and knowledge, and provide an overview of recommendations regarding prioritized risks as well as the scope and definition of the work. The analysis focus on two aspects of climate change; snow and heavy rainfall. The result from the analysis shows varying probabilities for snowfall, with less than a 1% chance annually for a blizzard day, 20-30% for snowfall over 6 cm, and 10-20% for snowfall over 25 cm. Overall, less snow is expected as more precipitation falls as rain in a future climate. Regarding heavy rainfall the result indicate increased precipitation in the future, especially for intense, short-duration rainfall events (shorter than 3 hours). Another conclusion is that future mean precipitation is higher across the board for both the emission scenarios. Based on the CLIMAAX analysis, a workshop was held on May 27, 2025, at the office of the county administrative board with the aim of informing and including relevant competencies in the county's climate adaptation work, based on the developed analysis. With this purpose in mind, a desired outcome was established, i.e., what the day would result in for the participants: • Show possible results that the CLIMAAX analysis can provide. • Participation in how the results can be used and developed as part of a regional action plan for climate adaptation. • Get input and local contribution to the analysis results that Norconsult can consider in the final report. The next phase of the project will see an in-depth analysis with local data and workshops with stakeholders. This will start in September 2025 and end in June 2026. For this phase, it is recommended that the purpose of the broader analysis with regards to its target audience is further established. Another crucial success factor is coordination, and it is highly recommended that a person is held in charge of coordinating the efforts. A list of important aspects with regards to the action plan has been compiled, see 4.1. Climate and vulnerability analysis for Västernorrland County Using the CLIMAAX Methodology Nr.: 109 60 66 Revision: 3 2025-08-14 | Sida 4 av 23 109 60 66 Climate and vulnerability analysis Content 1 Background 5 1.1 The county administrative board, its role and previous work with regards to climate adaptation 5 Earlier work 5 1.2 The CLIMAAX project 7 1.3 Purpose 7 2 Implementation of the CLIMAAX analysis 8 3 CLIMAAX analysis for Västernorrland 10 3.1 Snow 10 County-based scenarios for snow 14 3.2 Heavy rainfall 15 County-based scenarios for heavy rainfall 18 3.3 Application 19 4 Discussion 20 4.1 Conclusion from the workshop on the CLIMAAX material 20 4.2 Further recommendation 21 5 References 22 Appendix Appendix 1 – Graphic output from CLIMAAX model Climate and vulnerability analysis for Västernorrland County Using the CLIMAAX Methodology Nr.: 109 60 66 Revision: 3 2025-08-14 | Sida 5 av 23 109 60 66 Climate and vulnerability analysis 1 Background 1.1 The county administrative board, its role and previous work with regards to climate adaptation The County Administrative Board is a governmental agency with regional responsibilities that works to ensure that national goals are implemented in the county. It coordinates efforts between the state, municipalities, and other actors in areas such as environment, urban planning, crisis preparedness, and climate. The County Administrative Board has a special assignment related to climate adaptation, with responsibility for coordinating, supporting, and monitoring the work within the county. This includes producing knowledge bases, analysing the impacts of climate change, providing guidance to municipalities and other actors, and promoting a long-term sustainable and resilient society. With the government ordinance (2018:1428) on climate adaptation work by authorities, all county administrative boards and other relevant sector authorities have been tasked to: o Develop climate and vulnerability analysis. o Formulate goals for the authority's climate adaptation work. o Develop action plans. The County Administrative Board also supports municipalities and produces knowledge bases, etc. In 2025, through the EU-funded CLIMAAX project, the County Administrative Board has received approved support to conduct an overview of climate and vulnerability analysis. CLIMAAX is an EU-funded project within the framework of the EU's Mission on Adaptation to Climate Change. The project aims to strengthen Europe's ability to adapt to climate change, especially in regions that are particularly vulnerable and have limited resources for adaptation, see 1.2 for more information. The CLIMAAX project consists of three phases where this report is a summary of phase 1. o Phase 1: Analyse the county's risks regarding heavy rainfall and snow, using the common method (April - August 2025). o Phase 2: In-depth analysis with local data and workshops with stakeholders (September 2025 - June 2026). o Phase 3: Identify the need for climate adaptation in a regional action plan (July - December 2026). Earlier work In 2018, the County Administrative Board of Västernorrland developed a regional action plan for climate adaptation. The plan identifies vulnerabilities in the county and suggests measures in areas such as physical planning, infrastructure, water management, natural environment, and human health (County Administrative Board of Västernorrland, 2018). The County Administrative Board's action plan states that the board has implemented and coordinated several important initiatives: o Municipal climate analysis: All municipalities have received support in analysing local climate challenges. o Networks and collaboration: A regional network for climate adaptation has been established with municipalities, the region, the Swedish Transport Administration, LRF, and other actors. Climate and vulnerability analysis for Västernorrland County Using the CLIMAAX Methodology Nr.: 109 60 66 Revision: 3 2025-08-14 | Sida 6 av 23 109 60 66 Climate and vulnerability analysis o Water supply: A regional water supply plan has been developed, and networks for drinking water issues have been established. o Information efforts: Thematic days, workshops, and targeted information to the public and businesses. o Proposed measures: About 40 specific measures have been identified, with priorities until 2030. In 2022, the County Administrative Board followed up on the measures proposed in the action plan (County Administrative Board of Västernorrland, 2022). The follow-up states that increased knowledge and access to guidelines have strengthened the county's climate adaptation capacity, that municipal plans increasingly take climate-related risks into account, and that collaboration between authorities, municipalities, and other actors has improved. However, several measures remain, especially in areas such as tourism, industry, and certain technical systems. Below is a summary of measures taken during the period 2018-2022: Knowledge and collaboration: o New analyses: Snow in future climate, impact on natural and cultural environments. o Digitization of historical drainage maps. o Development of map services (Climate-GIS). o Active regional network with municipalities, authorities, and universities. Municipal work: o Sundsvall and Härnösand have adopted climate adaptation plans. o Several municipalities have integrated climate risks into comprehensive plans. o Project support has been given for e.g. cloudburst analysis and geotechnical surveys. Infrastructure and buildings: o The Swedish Transport Administration has identified vulnerable points in the road and railway network. o Municipalities have started using climate factors in stormwater investigations. o GIS analysis of cultural environments in risk areas has been carried out. Water and technical systems: o More municipalities have developed VA plans and cloudburst analyses. o Water protection areas are being reviewed. o Climate adaptation of drinking water supply has begun. Health: o Region Västernorrland has held seminars on climate and health. o Guidelines for managing heatwaves have been distributed. Agriculture and tourism: o Climate analysis for agriculture has been developed. o Sámi villages have received support to develop vulnerability analysis. o The forestry program includes climate adaptation. Natural environment: o Report on climate impact on natural environment and biodiversity. o Work with invasive species has been strengthened. Climate and vulnerability analysis for Västernorrland County Using the CLIMAAX Methodology Nr.: 109 60 66 Revision: 3 2025-08-14 | Sida 7 av 23 109 60 66 Climate and vulnerability analysis 1.2 The CLIMAAX project CLIMAte risk and vulnerability Assessment framework and toolboX (CLIMAAX) is a 4-year Horizon Europe project, started in January 2023 and runs until December 2026. The purpose of the project is to contribute to the harmonization and consolidation of the practice of climate risk assessment. The project provides financial, analytical, and practical support to improve regional climate and emergency risk management plans. CLIMAAX builds upon existing risk assessment frameworks, methods, and tools, and promotes the use of datasets and service platforms for local and regional scale deployment. CLIMAAX is designed to contribute to the harmonization of the practice of climate risk assessment (CRA) by providing: 1. A standardized CRA framework built on current community experience and best practices. 2. A toolbox for conducting risk analysis, which hosts data, models and utilities and provides access to European and global open data archives integrated with local data and procedures. 3. Five European pilot regional CRAs to shape the framework and toolset. 4. Financial support for at least 50 regions to execute a context specific CRA. 5. CRA guidance material and online helpdesk for other European regions. 6. A proposal to upscale results into the future operationalization of the regional CRA support function. The CLIMAAX CRA Workflow provides tools and datasets that you can use for your regional climate risk assessments. The Workflow is designed in such a way that it can be used by any region while maintaining a high level of flexibility to adjust it to the needs of your region! This might include replacing European datasets with local datasets, adjusting parameters of the assessment, or changing the visualization. 1.3 Purpose The purpose of this report is to briefly present the climate-related risks identified from the CLIMAAX analysis, how these relate to previous experiences and knowledge, and provide an overview of recommendations regarding prioritized risks as well as the scope and definition of the work. Climate and vulnerability analysis for Västernorrland County Using the CLIMAAX Methodology Nr.: 109 60 66 Revision: 3 2025-08-14 | Sida 8 av 23 109 60 66 Climate and vulnerability analysis 2 Implementation of the CLIMAAX analysis Risk assessment of heavy snowfall and snowstorms. The analysis was carried out according to the methodology described within the CLIMAAX project, with the support of published Python scripts and available data (CLIMAAX, 2025) (GitHub, 2025). The work followed the instructions in the document “Heavy snow and blizzards – workflow for risk assessment under climate change”, which can be found in the CLIMAAX manual and the associated GitHub repository (CLIMAAX, 2025). This workflow was developed to assess the risk of heavy snowfall and snowstorms in Europe but has in this application been adapted to specifically analyse Västernorrland County. The purpose of the analysis was to investigate where and how often extreme snow events occur today and how these may change in the future due to climate change. The analysis was based on indicators reflecting impacts, such as combinations of low temperature, heavy precipitation, and strong winds. The basis consisted of climate data from both observations (ERA5 dataset) and climate models (EURO-CORDEX dataset). Initially, Västernorrland was defined as the geographical analysis area. Climate data were then downloaded via an automated system (API) from the Copernicus Climate Data Store for two different time periods: a historical period (e.g., 1991–1995) and a future period (e.g., 2046–2050). Various emission scenarios were downloaded, such as RCP 2.6, RCP 4.5, and RCP 8.5. For more information on RCP scenarios, see chapter 3. The script was modified to include the entire snow season, from October to March. Using daily temperature and precipitation data, snow depth was calculated, and indicators for snowstorms and heavy snowfall were identified. Examples of such indicators are days with more than 6 cm or 25 cm of snow, as well as days when all three criteria – snow, cold, and strong wind – are met, which is classified as a snowstorm. The results were presented in probability maps showing the annual risk of heavy snow events in Västernorrland, both under current and future climate conditions. After the risk assessment was carried out, an exposure analysis was performed where the results were linked to population data. Here, data from the JRC data portal, specifically the Global Human Settlement Layer (GHSL), with a spatial resolution of approximately 1 km x 1 km, were used. To enable overlaying these data with climate indicators, the script was modified to reproject both datasets to the same geographical resolution and extent. The original code published on GitHub did not work as intended, and additional adjustments were made to the visualization functions as one of the maps previously overlapped another. Once the data had been processed and harmonized, particularly vulnerable areas were identified, where the population is at the greatest risk during extreme weather events. The final visualizations were then produced. Finally, the CLIMAAX support team was informed via email about the changes made to the original code. Risk assessment of heavy rainfall. The analysis of extreme precipitation in Västernorrland was carried out according to the methodology described in the CLIMAAX project's handbook “Heavy Rainfall” (CLIMAAX, 2025). The work was carried out using published Python scripts available via the associated GitHub repository (GitHub, 2025). The purpose of the workflow is to identify how extreme precipitation may change in future climate scenarios and how these changes may affect risk levels in a given geographical area. The method is developed for European conditions but has in this case been specifically adapted for Västernorrland County. The analysis was based on climate models from the EURO-CORDEX dataset with a spatial resolution of approximately 12.5 km. The focus was on two time periods: a historical reference period (e.g., 1976–2005) Climate and vulnerability analysis for Västernorrland County Using the CLIMAAX Methodology Nr.: 109 60 66 Revision: 3 2025-08-14 | Sida 9 av 23 109 60 66 Climate and vulnerability analysis and a future period (2041–2070) under emission scenarios RCP 4.5 and RCP 8.5. From the climate models, annual maximum precipitation values for different durations, such as 3 hours and 24 hours, were extracted, followed by an extreme value analysis using the General Extreme Value (GEV) distribution. Based on this, precipitation values for different return periods, such as 10-, 50-, and 100-year rains, were calculated. The results were visualized in the form of IDF (Intensity-Duration-Frequency) maps, showing expected precipitation for different return periods and durations, as well as change maps illustrating the percentage difference between historical and future climates. The following modifications have been made to the original script: all files have been reprojected, as the results initially did not appear within the Västernorrland area. The CLIMAAX support team has been informed of this adjustment via email. In the final step of the analysis is, the changed precipitation patterns were linked to local impact thresholds to perform a more detailed risk assessment. This script also required modifications, as it was originally written for an example from Catalonia and by default downloaded data for that area. The script also lacked functionality to import the results from previously conducted calculations. Therefore, this part was recoded so that the correct files from Västernorrland could be read, and these were reprojected again because the projection once again did not work as expected. The CLIMAAX support team was also informed of these adjustments via email. Afterward, the remaining parts of the script could be run without major adjustments, up to the final code step where different climate models are to be compared with each other. However, this step requires downloading 30 years of raw data for several different models and repeating the entire analysis, which was beyond the scope of the project. Climate and vulnerability analysis for Västernorrland County Using the CLIMAAX Methodology Nr.: 109 60 66 Revision: 3 2025-08-14 | Sida 16 av 23 109 60 66 Climate and vulnerability analysis As climate change accelerates, Sweden is expected to be more prone to raining than snowing during the winter season, as discussed in the earlier chapter. The county-based scenarios for Västernorrland with regards to heavy rainfall shows a general increase of about 20 % rain in both RCP-scenarios. In 2015, the County Administrative Board developed a county-wide low point mapping, including flow paths. This mapping is fully available in the County Administrative Board’s Climate GIS, as well as for each municipality. The municipalities of Sundsvall and Härnösand have since developed their own more detailed analysis for their central urban areas. In 2022, the Swedish Civil Contingencies Agency (MSB) was commissioned by the government to develop a standardized method for cloudburst mapping in urban areas. The assignment also includes applying the method to a selection of previously conducted cloudburst mappings and making the results available so that they are comparable from a national perspective. The CLIMAAX-analysis shows expected precipitation levels for different return periods (e.g., 10and 100year rainfall events) for both historical climate (1976–2005) and a future scenario (2041–2070). The method is based on annual maxima from EURO-CORDEX (~12 km), statistical distribution fitting (GEV), and calculation of changes in intensity (%). The results indicate increased precipitation in the future, especially for intense, short-duration rainfall events (shorter than 3 hours). Another conclusion is that future mean precipitation is higher across the board for both the RCP4.5 scenario and the RCP8.5 scenario, see Figure 3.7 and Figure 3.8 respectively. Climate and vulnerability analysis for Västernorrland County Using the CLIMAAX Methodology Nr.: 109 60 66 Revision: 3 2025-08-14 | Sida 17 av 23 109 60 66 Climate and vulnerability analysis Figure 3.6. Mean precipitation for 24h duration events over Västernorrland county, RCP4,5 (2041-2070) vs. historical (1976-2005) Figure 3.7. Mean precipitation for 24h duration events over Västernorrland county, RCP8,5 (2041-2070) vs. historical (1976-2005) The charts below shows the highest precipitation values (mm) for each year during the period 2041–2070, with a duration of 3 hours. As expected, the average precipitation is higher in the RCP8.5 scenario than the Climate and vulnerability analysis for Västernorrland County Using the CLIMAAX Methodology Nr.: 109 60 66 Revision: 3 2025-08-14 | Sida 18 av 23 109 60 66 Climate and vulnerability analysis RCP4.5 scenario. In the RCP4.5 scenario that precipitation varies between 9 to 21 mm and in the RCP8.5 scenario it varies between 7 and 29 mm. Figure 3.8. Annual maximum precipitation for 3h duration in Härnösand, RCP 4,5. Figure 3.9 Annual maximum precipitation for 3h duration in Härnösand, RCP 8,5. All the results from the CLIMAAX modelling done in this project are presented in Appedix 1. County-based scenarios for heavy rainfall In the county-level climate analysis presented by SMHI in 2015, calculations were provided describing meteorological and hydrological conditions in a future climate. The report states that the annual average precipitation is expected to increase by approximately 20–40% towards the end of the century. The largest increase occurs in spring, where the RCP8.5 scenario indicates a 50% rise in precipitation in certain areas. Heavy rainfall events, or cloudbursts, are also projected to increase by 15–25%, depending on the chosen RCP scenario. The geographic distribution of maximum daily precipitation shows a concentration in coastal areas. Similarly, maps of annual and seasonal average precipitation indicate the highest amounts in coastal regions. This pattern is likely explained by moisture supply from the sea combined with significant elevation differences between sea and coast—factors that are expected to persist in the future. Climate and vulnerability analysis for Västernorrland County Using the CLIMAAX Methodology Nr.: 109 60 66 Revision: 3 2025-08-14 | Sida 19 av 23 109 60 66 Climate and vulnerability analysis 3.3 Application The results from the CLIMAAX analysis show a general trend that is also evident in previous reports from SMHI (2015), namely that future climate change will lead to a warmer and wetter climate with reduced snowfall in favour of increased rainfall. The results can serve as a strategic-level planning basis but need to be complemented with local analyses based on the geography and unique circumstances of the county. The following section discusses how the results from the CLIMAAX analysis can be translated into an action plan and how that plan should be defined and clarified. Climate and vulnerability analysis for Västernorrland County Using the CLIMAAX Methodology Nr.: 109 60 66 Revision: 3 2025-08-14 | Sida 20 av 23 109 60 66 Climate and vulnerability analysis 4 Discussion 4.1 Conclusion from the workshop on the CLIMAAX material Based on the CLIMAAX analysis, a workshop was held on May 27, 2025, at the county administrative board with the aim of informing and including relevant competencies in the county's climate adaptation work, based on the developed analysis. From this purpose, a desired outcome was established, i.e., what the day would result in for the participants: • Show possible results that the CLIMAAX analysis can provide. • Participation in how the results can be used and developed as part of a regional action plan for climate adaptation. • Input and local contributions to the analysis results that Norconsult can consider in the final report. During the workshop, the participants were shown the results of the analysis and then divided into groups for discussion. The following questions were discussed: • Question 1 based on the CLIMAAX analysis: What needs to be done to develop a regional action plan for climate adaptation? • Question 2: How do you utilize the entire organization's collective competence in the work? • Question 3: Which proposals do you want to proceed with? • Question 4: How can the proposals become part of the ongoing work in the field? The workshop was documented, and the following inquiries were raised concerning the aforementioned questions. Important questions to answer for a climate action plan (gross list): • What are the project conditions? (Schedule, budget, and project group) • What needs should the climate action plan meet? • What is an appropriate goal image based on the needs? • What is an appropriate scope for the action plan based on the county administrative board's role and responsibility? • Who is the target audience for the action plan? • Which climate factors does the action plan need to cover? • Which types of analysis lack data concerning climate adaptation in the county? • How can we utilize the comprehensive data developed by other county administrative boards and authorities around the country? • How can the results be presented in a straightforward way? • What is already being done in municipalities that needs to be considered in the action plan? • What time perspective does the climate action plan need to cover? • How do we ensure that the action plan becomes useful and reaches the target audience? • How will the action plan be followed up and become part of the boards’ plan? • What lessons from historical climate-related events in the county need to be considered in the action plan? • How do we ensure that the implementation of the action plan does not become dependent on the project coordinator? Key points - based on the discussion of all questions during the workshop. Climate and vulnerability analysis for Västernorrland County Using the CLIMAAX Methodology Nr.: 109 60 66 Revision: 3 2025-08-14 | Sida 21 av 23 109 60 66 Climate and vulnerability analysis • Do not reinvent the wheel: o Start from and compile data from the previous climate action plan. o Start from work done by other county administrative boards and authorities. • Let the climate action plan cover both positive and negative consequences. • Where possible: Achieve two aims at once – combine climate adaptation work with ongoing work in, for example, preparedness/crisis management. Which questions/proposals are most important to proceed with/start with? • A common goal image is a crucial starting point: For whom are we making the action plan? What benefit should the action plan result in? • It is important to utilize existing material (What local data can be utilized? How have other county administrative boards designed and limited their climate action plans? • Map out important ongoing initiatives in the county that can be used/considered in the climate action plan (e.g., work within the flood directive). • What are the most important climate adaptation measures in the county? (It is important to prioritize measures with great potential benefit). • It is important to ensure procedures for following up the action plan and how it can become a natural part of the annual business plan. • Be as concrete as possible so that it is clear who is responsible for what in the climate action plan. • Where to turn if you want to apply for funds for climate adaptation measures? 4.2 Further recommendation The next phase of the project will see an in-depth analysis with local data and workshops with stakeholders. This will start in September 2025 and end in June 2026. For this phase, it is recommended that the purpose of the analysis with regards to its target audience is further established. Another crucial success factor is coordination, and it is highly recommended that a person is held in charge of coordinating the efforts. Before engaging in further analysis and workshops it is further recommended that: • All involved parties have knowledge about what a changing climate entails and why climate adaptation is important. • The older analysis is reevaluated in terms of its methods and coordination efforts. • The coordinator establishes a working group and that the members hold deeper knowledge of how the county is affected by a future climate with regards to different sectors. • The coordinator and the working group understand how climate change impacts vulnerable groups. • Climate adaptation has been anchored and prioritized in the management. It is recommended that the coordinator and the working group identify other relevant plans and programs to use the synergy effects. • One or two civil servants have been appointed to be responsible for coordinating and managing the climate adaptation efforts. • Ensure that the working group understands the dimensions of just (equitable) climate adaptation and that this is integrated into the work. Climate and vulnerability analysis for Västernorrland County Using the CLIMAAX Methodology Nr.: 109 60 66 Revision: 3 2025-08-14 | Sida 22 av 23 109 60 66 Climate and vulnerability analysis 5 References Bednar-Friedl. (2022). Europe. Climate Change 2022: Impacts, Adaptation, and Vulnerability.Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). CLIMAAX. (den 16 juni 2025). CLIMAAX CRA Handbook. Hämtat från https://handbook.climaax.eu/intro.html CLIMAAX. (2025). Extreme precipitation: Changes under climate scenarios workflow. Hämtat från CLIMAAX: https://handbook.climaax.eu/notebooks/workflows/HEAVY_RAINFALL/01_Extreme_precipitation/Ext reme_precipitation_Intro.html CLIMAAX. (2025). Heavy snow and blizzards - workflow for risk assessment under climate change. Hämtat från Handbook CLIMAAX: https://handbook.climaax.eu/notebooks/workflows/SNOW/01_Heavy_snowfall_and_blizzards/Risk_w orkflow_description_SNOW_BLIZZARDS.html Github. (2025). Hämtat från Github: https://github.com/CLIMAAX Github. (2025). Github. Hämtat från Heavy Rainfall: https://github.com/CLIMAAX/HEAVY_RAINFALL IPCC. (2021). Summary for Policymakers. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Länsstyrelsen i Västernorrland. (2018). Regional handlingsplan för klimatanpassning i Västernorrlands län. 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