Paradox: cold weather phenomenon – high fire danger index

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Prescribed Fire in NW Germany, 23 Feb 2018

Central Europe is experiencing a rare weather phenomenon:

A polar vortex has caused Arctic air to suddenly warm up and send freezing cold south towards Central Europe, which has already suffered days of frigid weather. The event, known as a Sudden Stratospheric Warming (SSW), usually chills for two weeks or longer and brings widespread snow. It has not occurred for four years, official government (UK) records show, and last time brought the coldest March for 51 years to Scotland for instance.

However, while Europe is preparing for cold, snow and ice, we can observe a paradox phenomenon: Before the expected snow and ice is arriving, the current weather conditions do indeed increase fire danger. Dry air with RH (relative humidity) dropping as low as 30% and winds gusting up to 60 km/h make ideal conditions to burn winter-dry fuels.

Traditional prescribed burning at this time of the year should be carried out only with wind under 30 km/h and with utmost care.

The Forest Service of Ireland for instance has issued a RED Fire Danger Index for the coming days: FIRE_DANGER_NOTICE_DAFM_ 27_February

irish_fires_27_feb_2018
Actives fires in western Ireland detected with AFIS Advanced Fire Information System mobile app. 27 Feb 2018…..following the risk analysis and red FDI Warning the day before. Source: C. Nugent

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