{"id":15611,"date":"2021-08-19T08:49:37","date_gmt":"2021-08-19T14:49:37","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=15611"},"modified":"2021-08-20T08:41:12","modified_gmt":"2021-08-20T14:41:12","slug":"spm-08-19-2021","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=15611","title":{"rendered":"SPM 08-19-2021: Heavy Rain, Flooding in Western Slope and Grand Valley"},"content":{"rendered":"

Issue Date: Thursday, August 19th, 2021
\nIssue Time: 9:35 AM MDT<\/p>\n

Summary:<\/h3>\n

As forecasted, a plume of monsoonal moisture rotating around a low-pressure to the west entered the western half of Colorado yesterday, bringing widespread<\/span>, heavy, long-duration rain to the Northwest and Southwest Slopes, Grand Valley, and even western portions of the Northern and Central Mountains. Afternoon thunderstorms produced an initial surge of heavy rainfall and even small hail, followed by waves of showers lasting overnight and well into the early morning. This prompted flood advisories and ultimately flood warnings for the Pine Gulch and Grizzly Creek burn scars, as well as a portion of the Cameron Peak scar.<\/p>\n

Due to the rural nature of the Pine Gulch burn area, there are limited observations. However, a total of 1.04 inches was recorded from a MesoWest gage in Demaree, just west of the burn scar. The time series plot below shows rain beginning around 6:00 pm and continuing until 6:00 am this morning. To the south, observations in Grand Junction range from 0.49-0.78 inches from CoCoRaHS<\/span> observers across town – similarly, rainfall totals are from afternoon storms and continuing showers overnight into morning.<\/p>\n

\"\"<\/a><\/p>\n

Observers in Glenwood Springs reported just about 0.5 inches of rain yesterday, however nearby Glenwood Canyon and the Grizzly Creek burn scar received over an inch and half of rain yesterday and overnight. The plot below of No Name Creek shows an accumulation of 1.44 inches, with continuous rainfall starting in the early afternoon and continuing through this morning.<\/p>\n

\"\"<\/a><\/p>\n

The flash flood<\/span> warning<\/span> issued for Glenwood Canyon prompted a safety closure of I-70 (after just reopening partially within the week). CDOT<\/span> shared the following information on twitter describing their approach to I-70 closures based on flood watches and warnings.<\/p>\n

\n

What happens during a Flash Flood<\/span> Warning<\/span>? CDOT<\/span> crews at the 2 closure points will close I-70. The @CSP_News<\/a> will sweep the area to ensure there are no motorists or members of the public in the area. Crews will continue to monitor the mudslide area.<\/p>\n

— Colorado Department of Transportation (CDOT<\/span>) (@ColoradoDOT) August 18, 2021<\/a><\/p><\/blockquote>\n