Due to severe storms expected today, the National Weather Service has issued a flash flood watch for all of Boulder County (and other cities and counties along the front range) and especially the Fourmile Burn Area. The watch is in effect from 2:00 p.m. to 12 midnight. Boulder OEM is monitoring the situation and will post updates as information changes.
Heavy rainfall increases the flow of sediment into our local streams and creeks, increasing the cloudiness. As a result of heavy rainfall over the Four Mile burn area, this sediment has been significant, contributing to a temporary discoloration of Four Mile and Boulder Creeks. The cloudiness and discoloration is an indicator of poor water quality and can mean an increased level of pathogens, such as E. coli and Giardia. People should always avoid drinking untreated and unfiltered water from streams, creeks, lakes, etc. Cloudy fast moving water may also have hidden debris that poses a safety risk, so people should avoid recreational activity in the creeks after heavy rainfalls or at a minimum exercise extreme caution.
Treatment plants for drinking water are designed to remove sediment and disinfect the water against pathogens, so the cloudy stream is not a concern for tap water. The city of Boulder does not draw any of its drinking water from these creeks.
The storm systems are tracking to the south and the risk appears to be low for the Fourmile Area, but not completely gone. Storms are expected to continue all night with diminished intensity and a southerly track. The flash flood warning has ended and all residents have returned to homes.
Another everbridge was sent to advise residents that the flash flood warning has expired but to remain vigilant due to weather still in the area. The only road closure presently is west of Emerson Gulch (off Fourmile Canyon Dr.) and is 4 feet deep and 100 yards wide. County road crews are building an emergency access through it and will go to work on removal of debris tomorrow.
The Emergency Operations Center will deactivate at 10:30 p.m
7/7 - 9:12 p.m. - County road maintenance crews are on scene with plows and road graders clearing the rock slides and debris flows. The goal is to get one passable lane in Fourmile Canyon tonight and go back tomorrow to widen the road.
7/7 - 8:39 p.m. - There are no reports of structure or infrastructure damage, other than debris flows on roads in the Fourmile area. Electricity and phones are working. No injuries have been reported.