1. Present and future risk of winter weather to critical infrastructure
Andrea Vajda,
Ilari Lehtonen, Matti Kämäräinen
Climate Service Centre
Finnish Meteorological Institute
EU FP7 project RAIN Workshop
17 Feb 2017, Helsinki
This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no The contents of this presentation are the author's views. The European Union is not liable for any use that may be made of the information contained therein.

2. Outline Identification of severe winter phenomena and their impact
European climatology of severe winter phenomena with focus on recent years
Projected changes in the probability of winter hazards in the future climate until 2100
Summary

3. Severe winter phenomena Snowfall Snowstorm (blizzard) Cold spell Winter storm Snow load Freezing rain

4. Severe winter phenomena Impacts on critical infrastructure
Heavy snowfall, blizzard, snow load and freezing rain can affect different type of CI
Road infrastructure
Blizzard,
March 2013, Hungary
Freezing rain,
Feb 2014, Slovenia
Heavy (coastal effect) snowfall,
2 Feb 2012, Finland
Energy & telecommunication
infrastructure
Feezing rain,
Dec 2010, Moscow
Heavy snow load,
Nov 2005, Germany
Heavy snowfall,
Feb 2013, Romania
Freezing rain,
Feb 2014, Slovenia
(AP Photo/Vadim Ghirda)
Railways
Freezing rain,
Feb 2014, Slovenia

5. Hazard identification – Surveys with stakeholders
28 CI stakeholders from the sectors:
Road management
Railways
Power transmission
Telecommunication
Rescue services
Most impacting phenomena:
Windstorms
Heavy rainfall
River floods
Snowfall & snowstorms
Freezing rain
RAIN Report:
Groenemeijer et al.: Past Cases of Extreme Weather Impact on Critical Infrastructure in Europe

6. Lat: 33 °N – 71°N
Lon: 11°W – 35 °E
Analysis of probabilities of hazardous winter events in the present climate
Heavy snowfall
Blizzards
Crown snow load
≥ 6 cm/24 h
≥ 25 cm/24h
Freezing rain
≥ 10 cm/24 h
≤ 0 ºC
≥ 17 m/s
> 20 kg/m2
> 60 kg/m2
> 5 mm/24 h
> 25 mm/24h
ERA-Interim reanalysis (0.7° grid)
E-OBS observational dataset (0.25° grid)
Methodology:
Impact thresholds defined for winter phenomena
Heavy snowfall and blizzards: impact thresholds applied directly on weather variables
Crown snow load: an operational algorithm used in weather prediction was applied
Freezing rain: freezing rain detection algorithm developed and applied
Output:
European gridded datasets of severe winter hazards
Frequency / Probability maps for each phenomena and impact thresholds

7. Average number of days/year with heavy snowfall
Present climate
Average number of days/year with heavy snowfall
>6 cm / day
>25 cm / day

8. Blizzard ≥ 10 cm/24 h, ≤ 0 oC, ≥ 17 m/s
Annual probabilities (%)
Blizzard ≥ 10 cm/24 h, ≤ 0 oC, ≥ 17 m/s
Crown snow loads >20 kg/m2
FMI crown snow load model:
rime + dry snow + wet snow + frozen snow =
total snow load

9. Annual probabilities (%) of freezing rain
Present climate
Annual probabilities (%) of freezing rain
> 5 mm / day
> 25 mm / day

10. Projected climate changes
Changes in temperature (°C) and precipitation (%) from 1971–2000 to 2070–2099, RCP8.5, multi-model means (28 GCMs)
Source: K. Ruosteenoja

11. What are the future projections for severe winter weather events?
Projected climate changes
Changes in temperature (°C) and precipitation (%) from 1971–2000 to 2070–2099, RCP8.5, multi-model means (28 GCMs)
6 RCMs from EURO-CORDEX simulations
Spatial resolution: 0.44°
Time resolution: 3–6 h
Scenarios: RCP4.5 (intermediate emissions)
RCP8.5 (high emissions)
Time period: 1971–2000
2021–2050
2071–2100
0.44° grid (≈50 km)
→ Multi-model mean: the mean change of six models compared to the reference period, for all the thresholds
→ Statistical significance of changes calculated with non-parametric Wilcoxon signed-rank test
Source: K. Ruosteenoja

12. Changes in annual probabilitiesby
Snowfall
Blizzard
>6 cm/day
>25 cm/day
New risk management and adaptation strategies might be needed!

13. Crown snow load > 20 kg/m2
Changes in annual probabilities by
Crown snow load > 20 kg/m2
Freezing rain > 5mm/day

14. Summary
Present climate:
Extreme snow events have the highest probability in northern Europe and the Alpine region, severe snowfall impacting mainly road and rail infrastructure are frequent also over Eastern Europe
Severe freezing rain impacts most frequently Eastern and South-Eastern Europe, and southern coast of Norway
Future climate:
Probabilities of snow-related hazards are projected to decrease over a large part of Europe but in N, NE Europe those may increase
Northward shift in the occurrence of severe freezing rain: slight decrease in probability in central Europe but intensification in Fennoscandia and Northern Russia
Finland: increased risk of hazardous winter phenomena → challenges for risk management and adaptation strategies
RAIN reports and Pan-European gridded data sets of severe weather probability are publicly available for end-users:
doi: /collection:ab70dbf9-ac4f-40a d38fdccd

15. 9 energy-relevant pan-European indicators of climate trends and variability