MAWECLI and MAWECLI2 – MArine and WEather events in the changing CLImate as potential external hazards to nuclear safety

MAWECLI and MAWECLI2 projects aim to increase preparedness towards single and compound marine and atmospheric extreme events that may pose external hazards at nuclear power plant level.

The photo shows arcus clouds on the leading edge of thunderstorms near the southern coast of Finland on 23 June 2021. Photo: Lassi Karvonen.

The objective of MAWECLI2 is to improve preparedness against exceptional marine and weather events that may challenge safety functions of the Finnish nuclear power plants. We utilise reanalysis and model datasets, extreme value and machine learning tools, and physical and statistical modelling to assess probabilities of the events in the changing climate. The results include estimates for unprecedented wintertime windstorms, jointly occurring strong wind gusts and heavy snowfall, severe thunderstorms, tornadoes, extreme sea levels, and high seawater temperatures.

The outcomes of MAWECLI project include improved estimates on coastal flooding risks, extreme air temperature, and worst-case flooding events caused by cyclones. We also produce estimates of the frequency and magnitude of high wind gusts and sea-effect snowfall systems, and joint effect of intense snowfall and high wind speeds, and make multi-hazard assessment for convective storms, meteotsunamis and lightning.

Project information

Funding: The Finnish State Nuclear Waste Management Fund through SAFER2028, National Nuclear Safety and Waste Management Programme 2023–2028 (http://safer2028.fi/)

MAWECLI2

Project duration: 1.2.2026–31.1.2029

Research topics: strong wintertime winds (extreme winds, high wind gust and intense snowfall), strong summertime winds (severe thunderstorms, tornadoes), marine extreme events (extreme sea levels, high sea water temperatures)

MAWECLI

Project duration: 1.2.2023–31.1.2026

Research topics: coastal floods, high wind speeds, sea-effect snowfall, temperature extremes, extreme sea level and waves due to cyclones, meteotsunamis due to convective storms, high winds and intense snowfall

Publications

2025

Laurila, T. K., Laapas, M., Olsson, T., and Jylhä, K. 2025. Wind speeds and gusts in Finland: a comparison of observations and ERA5 reanalysis. Boreal Environment Research 30: 181–193.

Ruosteenoja, K. , and Jylhä, K. 2025. Extreme Cold Days and Spells in Northern Europe at 0.5°C–2.0°C Global Warming Levels. International Journal of Climatology 45, no. 9: e8875.

2024

Rantanen, M., van den Broek, D., Cornér, J., Sinclair, V. A., Johansson, M. M., Särkkä, J., Laurila, T. K., and Jylhä, K., 2024. The Impact of Serial Cyclone Clustering on Extremely High Sea Levels in the Baltic Sea, Geophysical Research Letters, 51, e2023GL107203.

Särkkä, J., Räihä, J., Rantanen, M., and Kämäräinen, M., 2024. Simulating sea level extremes from synthetic low-pressure systems, Nat. Hazards Earth Syst. Sci., 24, 1835–1842.

2023

Pellikka, H., Johansson, M. M., Nordman, M., and Ruosteenoja, K., 2023. Probabilistic projections and past trends of sea level rise in Finland, Nat. Hazards Earth Syst. Sci., 23, 1613–1630.

Ruosteenoja, K., and Jylhä, K. 2023. Heatwave projections for Finland at different levels of global warming derived from CMIP6 simulations. Geophysica, 58, 47–75. Räty, O., Laine, M., Leijala, U., Särkkä, J., and Johansson, M. M., 2023. Bayesian hierarchical modelling of sea-level extremes in the Finnish coastal region, Nat. Hazards Earth Syst. Sci., 23, 2403–2418.

Reports

Reports are available on SAFER2028 TAG 1.1 website

2024

Räty, O., Laine M. 2024. D1.1.4 Review of spatial modelling of sea level extremes. Finnish Meteorological Institute. 29 p.

2023

Leijala, U., Särkkä, J., Johansson, M. 2023. D1.1.1 A literature review on future global mean sea level rise and ice-sheet instability. Finnish Meteorological Institute. 14 p.

Abstracts, posters and presentations

2025

Laurila, T. K., Mäkelä, A., Hautala, J., Rauhala, J., Särkkä, J., and Leijala, U.: Identifying meteotsunamis based on lightning observations over the Finnish sea areas, EMS Annual Meeting 2025, Ljubljana, Slovenia, 7–12 Sep 2025, EMS2025-94, https://doi.org/10.5194/ems2025-94, 2025

Olsson, T., Laurila, T., Aaltonen, A., and Jylhä, K.: Statistics of co-occurring extreme wind speed and snowfall in Finland, EMS Annual Meeting 2025, Ljubljana, Slovenia, 7–12 Sep 2025, EMS2025-244, https://doi.org/10.5194/ems2025-244, 2025.

Särkkä, J., Kanarik, H., and Tuomi., L.: Estimating storm surges and waves from synthetic low-pressure systems, 4th International Workshop on Waves, Storm Surges, and Coastal Hazards, Santander, Spain, 22–26 Sep 2025

2024

Laapas, M., Jylhä, K., and Ruosteenoja, K.: Annual probabilities of extreme air temperatures in the past and future climate of Finland, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-706, https://doi.org/10.5194/ems2024-706, 2024.

Virman, M., Jylhä, K., and Olsson, T.: Sea-effect snowfall in Finland in 1998-2018 based on convection-permitting climate model data, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-493, https://doi.org/10.5194/ems2024-493, 2024.

2023

Rauhala, J.: Derechos in Finland, 11th European Conference on Severe Storms, Bucharest, Romania, 8–12 May 2023, ECSS2023-117, https://doi.org/10.5194/ecss2023-117, 2023.

Rauhala, J.: A derecho in northern Europe, 11th European Conference on Severe Storms, Bucharest, Romania, 8–12 May 2023, ECSS2023-149, https://doi.org/10.5194/ecss2023-149, 2023.

Rantanen, M., Sinclair, V., Särkkä, J., Johansson, M., Laurila, T., and Jylhä, K.: The impact of serial cyclone clustering on extremely high sea levels in the Baltic Sea, EMS Annual Meeting 2023, Bratislava, Slovakia, 4–8 Sep 2023, EMS2023-195, https://doi.org/10.5194/ems2023-195, 2023.

Preceding projects

MAWECLI and MAWECLI2 are continuation of previous projects EXWE and PREDICT since 2007 (see details below).

PREDICT: Web page of PREDICT project

EXWE: Presentations and publications (PDF) of EXWE project

27.2.2026