Flash floods in Colorado VS

[Karel]

Sinds gisteren is ook de herfst in de VS ingevallen met veel regen en een flinke afkoeling in het oosten.
Het gevaarlijkst zijn echter de flash floods in Colorado in het zuid-westen van de VS. Zelfs de Universiteit in Boulder heeft er veel overlast van. Oorzaak is een koudeputje uit het noord-westen en stagnerende vochtige lucht die tegen de bergen wordt gelift.

"The National Weather Service in Denver has issued a Flash Flood Warning for: Northern Jefferson County in northeast Colorado. Boulder County in northeast Colorado.
• Until 6:00 am MDT Friday.
• At 11:53 pm MDT, emergency management reported a new round of severe flash flooding in Fourmile Creek, Boulder Creek, and lefthand Canyon in Boulder County. This is a flash flood emergency for the Fourmile burn area, the City of Boulder, and lefthand Creek. Seek Higher Ground now! This is a potentially life threatening Situation!.
• Some locations that will experience flooding include: Western Arvada, Western Westminster, Boulder, Western Longmont, Southwestern Broomfield, Lafayette, Northwestern Golden, Louisville, Superior, Lyons, Nederland, Jamestown. Ward, Salina, Niwot, Eldora, Allenspark, wallstreet, Rocky Flats, Brainard Lake, white Ranch open space, Eldorado Springs, Crisman, Gold Hill, Summerville, Peaceful Valley. Raymond, Meeker Park, sunshine and Longs Peak. At 11:50 pm, Boulder County Emergency Management reported significant rises coming down Fourmile Creek out of the Fourmile burn area and into Boulder Canyon. This surge is expected to reach the mouth of Boulder Canyon in the city of Boulder within the next 20 minutes. There was also a 10 foot wall of water coming down lefthand Canyon. Residents downstream can expect a significant increase in water levels, even east of the Canyons, over the next hour. If you are near Boulder or Fourmile creeks, get to higher ground now! Do not try to outrun this flash Flood!.
Recommended actions
Move to higher ground now. This is an extremely dangerous and life threatening situation. Do not attempt to travel unless you are fleeing an area subject to flooding or under an evacuation order. This is a life threatening situation. Heavy rainfall will cause extensive and severe flash flooding of creeks, streams, and ditches in the Fourmile burn area. Some drainage basins impacted include Fourmile Creek, gold run, and Fourmile Canyon Creek. Severe debris flows can also be anticipated across roads. Roads and driveways may be washed away in places. If you encounter flood waters, climb to safety.
Move to higher ground now. Act quickly to Protect Your Life."
http://www.weather.com/news/weather-severe/colorado-flooding-live-updates-boulder-denver-20130912

[Karel]

Colorado beschouwt dit event als "one in a thousand years". http://www.washingtonpost.com/blogs/govbeat/wp/2013/09/16/colorado-rarely-experiences-flooding-disasters/

[Karel]

Een overzicht van de flash floods in Colorado is hier te vinden.http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2013/09/16/colorados-biblical-flood-by-the-numbers/

[Edward]

Reed Timmer (bekend van het storm chasen) meldde zelfs een neerslagsom van 21 inch (530 mm) op 5 km zuidoost van het centrum van Boulder.

[Oud-forumlid]

En tot dit jaar was de natste maand in Boulder mei 1995 met 244 mm. Geniaal bezig daar.

Millenniumvloed, zeggen ze? Dan weet je het wel weer. Tweemaal per decennium bij de huidige klimaatstand. Neemt alleen maar toe die kans.

[Karel]

Door the University of Colorado, NOAA ESRL Physical Science Division and the CSU Colorado Climate Center is deze flash flood in historisch perspectief gezet. http://wwa.colorado.edu/resources/front-range-floods/assessment.pdf