Historic Flooding in Boulder, CO – Three Months of Rain in 48 Hours Sep 12, 2013
 September 12, 2013.

* Historic flash flooding underway in Boulder, Colorado from persistent rain/T-storms.

* State of Emergency in Boulder County.

* National Weather Service calling this a 10-25 year event.

* As much as 6-8″ rain has already fallen, another 1-2″ expected today; northern suburbs of Denver most at risk.

* Great link to real-time Twitter updates on Boulder flooding, road and business closures here.

* Colorado University at Boulder: minor damage to academic buildings.

* 400-500 grad students/faculty members displaced from housing adjacent to Boulder Breek

* Additional water released from Olympus Dam. 5 dams breached in Lyons, CO.

* Lyons Elementary School used as evacuation shelter – wastewater plant breached in Lyons.

* Multiple homes collapsed/destroyed in Jamestown (1 fatality).

* Broomfield: cars submerged by flooding, at least one motorists pulled out alive.

* Evacuations underway in many communities within and outside of the Boulder metro area.

* National Guard choppers grounded by flog/low clouds.

Here are some images from our affiliate 9News/KUSA

Broomfield Cars submerged from 9News/KUSA



Embassy Suites Flooded Parking lot Havana, CO from David via 9News/ KUSA


North Boulder Road in Boulder, CO from Justin via 9News/KUSA


Waterfall in Aurora, CO from Larry via 9News/KUSA


3 Months Worth Of Rain In One Night. The combination of an ex-tropical storm in the Pacific pushing into the southwest with a stalled pattern (trough of low pressure stuck over the Front Range) has created extreme rainfall amounts, focused on the Boulder area, over the past 24 hours. Rain is forecast to linger into tomorrow – another 1-2″ of rain is likely, so the flood situation will probably get worse before things slowly improve over the weekend.


24 Hour Rainfall Amounts. As much as 6-8″ has been reported in the Boulder area in the last 48 hours. The ground is saturated, unable to soak up any more rainwater – resulting in severe to extreme flash flooding, in the city of Boulder, but also the neighborhoods and canyons outside Boulder.

Stalled Pattern. A temporarily stalled storm near Salt Lake City, coupled with a flow of tropical moisture from the Pacific and Mexico, is focusing repeated T-storms over the Front Range. Additional flooding is likely in the Denver area, but the worst conditions will continue to be found closer to Boulder. No significant improvement is likely until Saturday or Sunday.Summary: Historic flash flooding is underway in Boulder, with minor/moderate flooding in the Denver area. The stalled storm responsible for this flooding will remain in place today, and begin to weaken tomorrow and over the weekend as conditions slowly ease. More evacuations are likely; additional dam breaches and canyon flooding can’t be ruled out.



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Welcome to the WeatherNation blog. Every day I sift through hundreds of stories, maps, graphics and meteorological web sites, trying to capture some of the most interesting weather nuggets, the stories behind the forecast. I’ll link to stories and share some of the web sites I use. I’m still passionate about the weather, have been ever since Tropical Storm Agnes flooded my home in Lancaster, PA in 1972. I’ve started 5 weather-related companies. “EarthWatch” created the world’s first 3-D weather graphics for TV stations – Steven Spielberg used our software in “Jurassic Park” and “Twister”. My last company, “Digital Cyclone”, personalized weather for cell phones. “My-Cast” was launched in 2001 and is still going strong on iPhone, Android and Blackberry. I sold DCI to Garmin in 2007 so I could focus on my latest venture: WeatherNation. I also write a daily weather column for The Star Tribune And if you’re on Twitter, you’ll find me @pdouglasweather

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