OURAY COUNTY – Mudslides and mushrooms provide the anecdotal evidence: It has been a wet monsoon season, so far, a judgment confirmed by National Weather Service data for July and (most of) August.
Dick Crabb, NWS observer in Ridgway since 1982, took a look back at recent summers and compared them to the summer of 2010.
“It’s different,” Crabb said. “I know it’s been damper” than the previous three years.
“For the first 22 days of August, for example, Ridgway has seen 3.02 inches of rainfall. That compares with the 0.14 inches for the full month last year. The average since 2007 is just over 1 inch.
According to NWS meteorologist Megan Schweitzer in Grand Junction, the 28-year average August precipitation for Ridgway is 2.12 inches. So, for the last few years, August has been quite dry.
But the 2010 numbers, at more than 150 percent of the long-term average, are still impressive.
Ouray has seen a wet August as well. From Aug. 1-22, the rain gauge has measured 2.6 inches of moisture, compared to the monthly average of 2.34 inches. July was the truly wet month for Ouray, with 3.98 inches against an average 2.13 inches.
Conversely, Ridgway didn’t see nearly as much rainfall in July, with 1.66 inches of water, compared to an average 2.04 inches. It just shows the variability of mountain weather, a few miles up or downstream, from one month to the next.
Statewide the monsoon has delivered varied results as well. According to figures from the Colorado Climate Center in Boulder, July was very wet across parts of southern Colorado and the southeastern plains. Trinidad got drenched by 6.84 inches of rainfall in July, three times the average, while Cortez doubled its monthly average. Denver was wetter than usual, too, logging 3.7 inches of precipitation, 171 percent of normal.
Conversely, parts of central and northern Colorado stayed relatively dry. Grand Junction was only 70 percent of normal for July (though it has been wetter in August). Montrose was average for the month, with just over 1 inch of water. Blue Mesa Lake received a paltry 31 percent of normal rainfall. Greeley and Fort Collins were at 87 and 67 percent respectively. Yampa, in north-central Colorado, received only half its usual 2 inches in July.
The nature of monsoon rains, with thunderstorms dropping a lot of water in a short period of time over concentrated areas, means that many of these totals came in bursts, rather than in sustained precipitation over hours or days. This is especially true in La Niña years, like this year, when the monsoonal regime slides farther north into Colorado.
Will the monsoon continue? Late August typically brings an end to the pattern. Meteorologists like Schweitzer and seasoned observers like Crabb shy away from predicting very far into the future. Drier air is expected to prevail up to today (Thursday). Then, according to the NWS website, “monsoon moisture is expected to surge back into the region and remain over the area through Monday.”