2:35 PM, Wednesday, March 23, 2016
There are a number of 20-inch reports as of 2PM not only in some foothills locations, but also in a corridor roughly along and a little west of I-25, including Wheat Ridge, Westminster, Broomfield, Louisville, and Lafayette Wouldn’t be surprised to see a few more. At 2PM the snow was decreasing from the north and west in Larimer, Boulder, and Jefferson counties. Heavy snow still persisted near and east of I-25. Parts of the Denver area (and DIA) may have to deal with significant snow and blowing snow into the early evening, and the storm is likely to rage into the night on the northeastern plains.
The intensity was amazing:
I got the storm position incorrect which made a big difference in shifting the action west toward the foothills last night. But just as important for the accumulation was the historic intensity of the snowfall rates. There were multi-hour periods of 2 inches per hour, and peak rates of 4 inches per hour! Snow adds up fast at those rates! As of noon the Boulder climate station topped 15 inches in just 10 hours, and that wasn’t as intense as some locations immediately to the east. An analogous storm occurred in March of 1992 when the Boulder climate station received 13 inches of heavy wet snow in 6 hours (with thunder), and 16 inches in 12 hours. Some areas immediately east got 20″ in that one too.
March and El Nino:
March averages the most snow of any month along the Front Range urban corridor, and El Nino years typically increase the odds of a snowy, wet March. After a very dry first half of the month, many parts of the Front Range are now on the snowy side of average, and we may add at least a little more Friday night or Saturday.