Cold Front Moving Through the Northeast U.S. Monday; Atmospheric River to Impact the Pacific Northwest Midweek

A cold front will cross the Great Lakes and Northeast U.S. through Monday with gusty winds and areas of rain showers. A strong atmospheric river is expected to move into the Pacific Northwest by midweek bringing a threat for moderate to heavy rainfall, gusty winds, and mountain snows for parts of Washington, Oregon, northern California, and the Sierra Nevada. Read More >

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.

April 11 Storm Reports

RADAR IMAGES


Base Reflectivity	Specific Differential Phase

Differential Reflectivity	Correlation Coefficient

SURVEY AND FLOODING IMAGES


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

Flooding in Etter, TX (Moore County)	Flooding in Etter, TX	Flooding in Etter, TX

Flooding in Etter, TX	Flooding in Etter, TX	Flooding in Etter, TX

AMA RSS Feed

Cold Front Moving Through the Northeast U.S. Monday; Atmospheric River to Impact the Pacific Northwest Midweek

April 11, 2012 Hail and Flood Survey