Aspects of climate extremes in Finland Ari Venäläinen, Kirsti Jylhä, Andrea Vajda, Tiina Kilpeläinen, Seppo Saku…

CLIMATE RISKS IN FINLAND storms low pressures, tornadoes, down bursts snow slipperiness icing fox turbulence floods an drought hot and cold spells lightning

Above 11 ms -1 wind cases on land areas (17 stations)

Number of storm days (>21 ms -1 ) at sea areas

Number of deep low pressures and rapid change of air pressure in Kajaani

Helsinki, Jokioinen, Sodankylä storms Year Deviation from mean (%) 980 hPa casesAbove 20 hPa change Above 9 hP gradient

How high wind speed we may experience?

TORNADOES Kontiolahti

Tornadoes in Finland

Tornadoes in different fujita classes F : 45 % : 8 %

1(2)

Climatological characteristics of precipitation in Helsinki

Daily precipitation Helsinki Return period (years) Preciptation (mm/day)

Return period of the duration (hour) of a rain event Summer rain events in Helsinki in : duration and precipitation amount Return period of precipitation amount (mm) in a rain event Ref: Tiina Kilpeläinen

1, 2, 3, 6 and 12 month precipitation amounts in Finland Monthly Two months Three months Six months Twelve months

1- month 2- months 3- months 6- months 12- months

Snow damages

Date Wind speed (m/s) temeperature (°C) Precipitation (mm) accumulated snow (kg/m2) windtemp accum.prec Kuusamo

Above 20 kg snow load on tree branches, days / 10 years

ACCLIM part of Finnish adaptation research Climate extremes and estimated climate change based on the latest climate scenarios In the first part of the study return periods of several parameters are calculated

DRY SPELL (< 50 mm), summer ret.per.304 Helsinki Kaisaniemi1101 Turku lentoasema 1201 Jokioinen observatorio 1501 Utti lentokenttä 2401 Jyväskylä lentoasema 3201 Kauhava lentokenttä (years)95 %ka95 % ka95 % ka95 % ka95 % ka95 % ka95 % Ret.per Joensuu lentoasema 5401 Oulu lentoasema 6801 Kuusamo lentoasema 7501 Sodankylä8201 Muonio kk9601 Inari (years)95 %ka95 % ka95 % ka95 % ka95 % ka95 % ka95 %

And the future? December 2006 mean temperature in Helsinki was +4.0 ºC and March 2007 temperature +3.1ºC. The return periods of this high temperatures is more than 500 years This two months demonstrate the difficulty to estimate the reliably the return periods in rapidly changing climate. How to explain all this to media and general public?