National Weather Service United States Department of Commerce
On the afternoon of May 28th, strong thunderstorms developed over southeast Washington and the southern Idaho Panhandle region. These storms moved very slowly to the northwest, which is a somewhat unusual direction for storm motion. One storm in particular though moved very little, anchoring itself over the hilly terrain northeast of Moscow, ID. The radar loop below shows the thunderstorm activity. Note the persistent strong storms between Potlatch and Deary. 
radar Loop

 

The persistent storm produced a very impressive hailstorm. This storm occurred along Highway 9 between Deary and Princeton.

Map of Hailstorm

 

The images below show the Idaho Highway Department clearing the highway of the hail. Some of the hailstones were as large quarters and accumulated to a depth of up to 4 inches.

 

Hail covering the fields

 

Plowing Hail

 

a close up of the hai

By Ron Miller and Kerry Jones