Hail Storm in Denver

Hail covers the ground on the west side of Denver September 9.
Credit: thedenverchannel.com

No, this is not a photograph of Denver during the winter. It's a photo taken Monday of hail covering the ground in the Denver Metro area. Thunderstorms left piles of hail up to five feet deep and produced flooding in Lakewood, Golden and Wheat Ridge.

There have been some impressive hail storms reported this year (New Mexico, Calgary) and this one is in that class. Winds on the west side of the ridge over the central U.S. have been pumping moisture from the Pacific across Mexico into Arizona and Colorado (the seasonal monsoon). The moisture has been fueling thunderstorms over this region the past few days and for a few more days to come.

Satellite water vapor image for 2:45 p.m. MDT Monday, September 9.
White and pink colors indicate moisture. Red and oranges depict dry air.
From NCAR Real-Time Weather Data web site.

Thunderstorms Monday afternoon produced frequent lightning, torrential rain and hail heavy enough to cover the ground in many places on the western edge of Denver.  Fortunately, according to hail reports submitted by CoCoRaHS observers most of the hail was pea-size (1/4") with some up to 1/2", and most of the damage was leaf damage. However, streets flooded as hail and debris clogged storm
drains.

"Hail floes" float on water covering street. Credit: thedenverchannel.com

Front-end loaders, backhoes, and dump trucks had to be used to clear streets where the hail had piled up to as much as five feet deep. In addition to the hail and the flooding the storms knocked out power to 9,600 power customers in the area.

Hail piled up on a street in Lakewood, CO.  Credit: thedenverchannel.com