The City of Longmont has activated our Emergency Operations Center as a precaution.

The Longmont OEM page is up.  Please watch for updates at www.longmontoem.org

The City of Longmont has activated our Emergency Operations Center as a precaution.  We have experienced some traffic light outages, but most have been fixed.  As a reminder, if the traffic lights are out, you must treat it like a four way stop.  

I’ve attached two weather updates.  A Flash Flood Warning for Larimer, Weld and Boulder County and a river update.  We are monitoring the St. Vrain River and Left Hand Creek.  Flows are listed below. 

Flash Flood Warning for Larimer, Weld, Boulder Counties, CO

Active for next 24 minutes · 

National Weather Service

This alert has been updated.

Posted 16 minutes ago

The Flash Flood Warning remains in effect until 10:15 pm MDT for Southeastern Larimer, Northeastern Boulder and southwestern Weld counties. At 9:19 pm MDT, the thunderstorm producing very heavy rain was located near Berthoud, or 19 miles south of Fort Collins, and was nearly stationary. Radar has indicated between 4 to 6 inches of rain has fallen halfway between Berthoud and Lyons with lesser amounts in the surrounding area between Riverside, Johnstown, Mead and hygiene. Runoff from the area with the heaviest rainfall will flow into Saint Vrain Creek between Lyons and hygiene and also on the little Thompson River southwest of Berthoud and produce flooding. Stream levels along Little Thompson River and Saint Vrain Creek could rise up very quickly.

Some locations that will experience flooding include: Southern Greeley, Longmont, Southwestern Loveland, Evans. Firestone, Johnstown, Milliken, Berthoud, Mead, Platteville. Lyons and Gilcrest.

The storm remains nearly stationary east of Lyons, north to Berthoud.  Around 2 inches of rain is possible in the warned area in the next couple hours.  This rainfall will exacerbate the flooding.

If you live in these areas follow these recommended actions.

Move to higher ground now. Act quickly to protect your life. This is becoming a very dangerous situation.

Excessive runoff from heavy rainfall will cause flooding of small creeks and streams, highways and underpasses. Additionally. Country Roads and farmlands along the banks of creeks, streams and other low lying areas are subject to flooding.




9:22 P.M. update

EOC open and staffed, our focus currently is on continuing the public information campaign and watching the rainfall over the St. Vrain drainage. 

Flood Warning issued until 9:00 tomorrow morning, 4 to 5 inches of rain has fallen in the Lyons area over the St. Vrain drainage.

No significant impacts to the City yet, the gauge at Lyons has risen 600 cfs in the last two hours.

Our concern at this point is flash flooding on the Lefthand and/or St. Vrain.  PD is monitoring both rivers.

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