Historically heavy September rains across parts of Colorado’s Front Range were called ‘biblical’ by the National Weather Service. The precipitation and resulting flooding was also referred to as catastrophic, epic, exceedingly rare, unprecedented, and the ‘100 year storm.’ The floods wreaked havoc across 17 Colorado counties and 2,000 square miles. In some areas rivers were reported as 1,000% of average and the flow rate, measured in cubic feet per second (cfs), at 10,000% of average! In Boulder, for example, more than 17 inches of rain fell in just over a week, breaking monthly and annual records in a place where precipitation averages about 19 inches a year. The numbers are staggering: 
  • ·  According to reports in the Denver Post, at one point Boulder's 25 square miles were awash in  an estimated 4.5 billion gallons of water.
  • ·  An acre-foot of water, the amount of water covering 1 acre (roughly the size of a football field) with a foot of water, equals 326,000 gallons. The equivalent of 13,803 acre-feet of water fell in the Boulder area.
  • ·  Boulder Creek hit a flow rate of 4,500 cfs, more than doubling the previous high flow recorded during the last quarter century. The river usually runs at 100 to 300 cfs.
  • ·  A cubic foot of water weighs 62.4 pounds. That means that at one point Boulder Creek was roaring with 280,800 pounds of water a second, or just over 140 tons. The standard railroad locomotive weighs 120 to 240 tons, depending on the model.
  • ·  Converting an inch of rainwater into the equivalent amount of snow is a bit tricky, given the variables. One inch of rain will produce 3½ to 4 inches of wet snow, but potentially 10 to 12 inches of light powder. With the amount of rain in Boulder, a powdery snow could have been up to the eaves of single-story homes. 
The destruction from the severe flooding on the Front Range is mind-boggling. Eight people lost their lives and thousands had to leave their homes. The number of people missing or unaccounted for statewide peaked at 1,200. In addition, houses were swept away by raging rivers, bridges were wiped out, numerous rock slides ensued, whole towns were isolated, and countless farm fields went under water.
Thankfully, all of Colorado's high-hazard dams, which likely would kill people if they fail, withstood the recent record rainfalls and floods. In Colorado, reservoirs are vital for: flood mitigation, water storage, hydroelectric power generation, and recreational use. As a precautionary measure, however, Colorado is undertaking the largest emergency dam inspection program in state history. They will be checking 200 dams in 10 days, mostly along the South Platte River and its tributaries. At least 55 engineers have offered to help the state dam safety branch with the inspections, and the agency has called all of its engineers in western Colorado to Denver. These engineers will, "help do a workload that would have taken us six months," said dam safety chief Bill McCormick. The inspectors will be looking for problems like increased seepage from large earthen dams, damaged spillways, and clogged drainage outlets.
Flood-prone areas have been identified in 267 cities and towns in Colorado and in all 64 counties. The Colorado Water Conservation Board (CWCB) encourages you explore whether you may be at risk and if so, to take precautionary mitigation measures. Visit www.floodsmart.gov or www.msc.fema.gov to determine your proximity to a flood zone.
In addition, for those who received loss or damage due to severe storms, flooding, landslides and mudslides, you may be eligible for disaster aid through FEMA and other programs. Counties that are currently covered by the Major Disaster Declaration are Adams, Boulder, Larimer, and Weld. To register, call 1-800-621-FEMA (3362) or register online at www.disasterassistance.gov.
Finally, relief assistance and efforts are desperately needed. Helpcoloradonow.org has compiled a list of organizations accepting donations, financial and material, which will go directly to help those affected by the floods. Please help in any way you can.