I've "googled" this in the past but was never able to find the answer. In an icing airmet, what does the top number mean? In the below illustration just captured off the aviationweather.gov site, I interpret the icing airmet over the Dakota's and Minnesota as the icing conditions between the surface and 10,000 msl. However, I do not know what the 22,000 msl is supposed to represent - any ideas?
