National Weather Service United States Department of Commerce


Event Summary
A severe and slow moving thunderstorm over northern Potter County, about 3 miles south of Masterson, brought a tremendous amount of hail and very heavy rain across U.S. Highway 287.  The National Weather Service doppler radar estimated that 5-6 inches of rain fell in a very small area in northern Potter County, approximately 26 miles north of Amarillo.  Most of this rain fell in one to two hours during the late afternoon.  Large hail, up to the size of golfballs, fell in addition to the heavy rain.  The runoff from the heavy rain pushed the hail into 3-4 foot drifts across Highway 287.  The highway was closed for over 12 hours due to the water flooding the roadway and the hail drifts.  The runoff from the heavy rain also caused a normally dry creek to rise about 15 feet, approximately 23 miles north of Amarillo.  The creek was reported to have risen to the bottom side of a bridge on Highway 287 (see images below).  A storm survey nearly 20 hours after the event revealed hail was still piled up to 3 feet in places and remained as large as ping pong balls!  At the bridge site, severe erosion of the bankment just downstream of the bridge was noted.
Storm Reports
April 11 Storm Reports


KAMA Base Reflectivity KAMA Specific Differential Phase
Base Reflectivity Specific Differential Phase
KAMA Differential Reflectivity KAMA Correlation Coefficient
Differential Reflectivity Correlation Coefficient


Hail drifts with ping pong ball size hail remaining 20 hours after the storm Mud and hail drifts Hail up to ping pong ball size
Snow plows pushed the hail off Highway 287 Heavy rain creates a tunnel in the hail drift Hail drift along the side of a creek
Water remains under a bridge on Highway 287 where flash flooding occurred Hail drift over 3 feet high Metal sign post bent by flood waters
 Flood waters create significant erosion. Flood
waters were reported to have risen to to bottom of the bridge
 Hail drifts along Highway 287 Hail bridge created by flash flooding
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