By Tom McGhee
12 September 2013
(The Denver Post) – The record-breaking rain that has dropped up to 10 inches in the metro area, tapered off a bit Thursday afternoon but is expected to come down with a vengeance again after 6 p.m., said Mike Nelson, chief meteorologist at Denver's Channel 7 News.
Flooding that killed three, and stranded motorists along the Front Range, is an event for the record books, a 100-year flood, that in some places dumped more than half the 15 inches of rain that is average for the region.
The National Weather Service has issued flash flood warnings through Thursday in all or portions of the following counties: Adams, Arapahoe, Boulder, Denver, El Paso, Fremont, and Larimer.
"We are looking at a flash flood watch going through late tonight," Byron Louis, program manager with the National Weather Service in Boulder, said.
The moisture that travelled north from above the equator collided with a cold front coming down from Canada, and the resulting weather has settled into place, Nelson said.
He called it a rare event, a storm that brings to mind a 1965 deluge that flooded downtown and led to the building of Chatfield Dam.
"What broke the heat wave on Monday was a cold front that came in and stalled," Nelson said. "At least through tomorrow, heavy rain is likely. Saturday and Sunday will be warmer, but we don't actually get dry until Monday."
Though rain has fallen sporadically since Monday, the bulk of the precipitation creating havoc throughout the metro region started on Wednesday evening. If it had been snow, Nelson said, area residents would be digging out of between 10 and 12 feet.
At 10 a.m. Thursday, the National Weather Service said the Front Range was already saturated: "Any further rainfall will have difficulty penetrating the ground and lead only to more runoff." By 11:30 a.m. Thursday, the skies had unleashed 8 to 9 inches of rain in parts of Boulder County, breaking the record for the month of September set in 1919 — 4.80 inches, Louis said.
Three hours later, totals in parts of Boulder and Larimer Counties had hit 10 inches and more, Nelson said. [more]