604 A Year in the Life of an Impact-Based Warning System

Tuesday, 8 January 2019
Hall 4 (Phoenix Convention Center - West and North Buildings)
Elín B. Jónasdóttir, Icelandic Meteorological Office, Reykjavik, Iceland

On November 1st 2017 the Icelandic Meteorological Office launched a new color coded impact-based warning system for weather. The system is based on the CAP 1.2 standard from WMO and is available to anyone to consume in XML and JSON formats on the IMO webpage.

Iceland has its shares of turbulent weather. Most common are synoptic cyclones with sharp warm, cold or occluded fronts, mountain waves, heavy showers of snow from the North Sea onto the north coast of Iceland, heavy rains from decaying hurricanes or tropical storms, windstorms and the odd thunderstorm and even tornado. After particularly challenging weather situations in 2012 and 2013 discussions about a new type of warning system, one where climatological thresholds would be abandoned and an impact-based system with a likelihood matrix would be adopted. Even though locals are well adapted to the harsh weather, increased mobility of the population, different needs for new industries and a different habitation pattern of Icelanders, along with the fact that we now receive over 2 million tourists every year made the need for a new system based on societal impact increased every year.

After several iterations of development and testing in 2016 and 2017 the system was launched in November of 2017. The first yellow warning was issued the day of the system‘s release, and the first orange warning was issued for 5th of November. During the next months the forecasters of IMO would issue 45 orange warnings and 98 yellow warnings. No red warnings have been issued to date.

The system launch and first year was a success on most levels. Close cooperation with The Icelandic Civil Protection Authorities, Coast guard, Search and Rescue, Aviation authorities and the Road Administration resulted in more preparedness and the public took well to the warnings. A few issues did arise. Yellow fatigue set in a few weeks after the system was launched, colours were taken at face value by the public, while the text and location of each warning within the warning matrix did not get enough attention. While wind and blizzard warnings verified well, rain and rain flood warnings did not.

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