Historic flooding crushes records in Colorado and surrounding states

Torrents of water fill the Bear Creek bike path as it passes underneath Moorhead Avenue on Thursday afternoon 9/12. (Bob Henson/UCAR)

Torrents of water fill the Bear Creek bike path in Boulder, CO, as it passes underneath Moorhead Avenue on Thursday afternoon 9/12. (Bob Henson/UCAR)

11:30 p.m. update: The Boulder Office of Emergency Management now reports that 172 people are unaccounted for amidst the largest federal search and rescue operation in Colorado history. Up significantly from reports this afternoon, preliminary numbers will often change a good deal in both directions. A fourth death has been confirmed from flooding.

3:21 p.m: What has been described as “biblical” flooding in parts of Colorado, New Mexico and Kansas persists today. At least three people have been reported killed by the flooding, with more than a dozen feared missing at present.

Warnings to evacuate have included the idea of leaving on foot rather than by vehicle, as some towns are virtually cut off by destroyed roadways. The Colorado Department of Transportation has also urged people to stay off roads throughout Boulder, Larimer, Jefferson and Clear Creek counties due to the number of locations impacted.

In part of Colorado’s “ground zero,” Boulder has now picked up at least 14.62″ of rain since the onslaught began a few days ago.

Much of that incredible total came yesterday.

According to Matt Kelsch (University Corporation for Atmospheric Research), Boulder’s coop observer, the September 12 rainfall of 9.08″ nearly doubled the previous all time daily record of 4.80″ tallied back on July 31, 1919.

Related: Interactive map of 3-day Colorado rainfall totals (Brendansweather.com)

Additionally, Kelsch notes that the previous monthly record of 9.59″ in May of 1995 has been destroyed by this event — almost in one day alone. Boulder is now also closing in on a yearly rainfall record of 29.93″ set back in 1995.

Though the death toll is thankfully lower than during the historic Big Thompson Flood of July 31, 1976, which killed 143 people, this event has surpassed it both in regional coverage and when looking at river stages in the area:

Bob Henson of UCAR shared what he’s witnessed in hard-hit Boulder. “In many ways this event reminded me of a Southeastern [U.S.] deluge: leaden skies, soupy air, and virtually nonstop precipitation,” he said in an e-mail today.

Regarding comparisons to past Colorado floods, Henson also wrote, “we’ve seen heavier one-hour rainfall rates along the Front Range during isolated summer thunderstorms, but the sheer duration and geographic scope of this event are truly astounding.”

While much of the attention has been on Colorado, major to historic flooding has also occurred along upslope areas in northwest Kansas and eastern New Mexico in particular.

Goodland, Kansas, for example, has seen over 6″ of rain in the past three days. About a once in 100 year occurrence, according to the National Weather Service office there.

Further south in New Mexico, major flooding has impacted the eastern half of the state. A flash flood emergency was still in effect this afternoon for places like Los Alamos, where landslides and significant flooding have been occurring.

Portions of New Mexico are expecting upwards of 10″ or more of rain by the time all is said and done.

Related: Flooding rains in the Front Range of Colorado (CIMSS Satellite Blog)

The good news, at least for some of the flooded areas in Colorado and Kansas especially, is that rainfall has shifted and let up a bit today. However, more rain is possible over coming days, and runoff will continue to flood portions of the region even if additional totals are more bearable.

84 hour rainfall prediction from the North American Mesoscale Model as of this morning. (Weatherbell.com)

84 hour rainfall prediction from the North American Mesoscale Model as of this morning. (Weatherbell.com)

Videos from Colorado

Colorado Gov. John Hickenlooper issued an update on the flooding situation in communities beleaguered by days of rain.
Officials in Boulder, Colo., say they’ve told about 4,000 people living around the mouth of Boulder Canyon to evacuate.

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