Mark Losleben - CU INSTAAR Research Staff
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Mark Losleben - CU INSTAAR Research Staff |
The following snowpack conditions on Niwot Ridge have been reported by Mark Losleben for March, 2003. Select here for more information about these snowpack reports
Greeting! What a difference one snowstorm can make! The C1 snowpack on Niwot Ridge, Front Range, Colorado, jumped about 50% with last weeks storm. The South Platte basin is now tops in the state, percentage-wise, but more on the storm later.
Manual measurements show the snowpack at C1 at 1230 MST 30 March 2003 to contain 16.75 inches of water in a 63 in deep snowpack. This is 129% of the 1982-2002 average, and the third highest amount in this record. The years 1996 (20.375") and 1984 (18.9") were higher. This months snowpack level represents a 48% increase over last months 81%, and is due mainly to the storm on March 17-19.
The above hand measurements compare well (by percent) with the SnoTel measurement which shows 128% of average snowpack at this same time. The snow water equivalents (SWE) are different, however. SnoTel reports 15.7" (versus hand measurement of 16.75"). This undermeasurement often occurs in the spring due to "bridging" of the snowpack over the sensing snow pillows, and the fact that the percentages are comparable, suggests that this is about the usual amount of bridging for this time of year. The SnoTel records also show the winter precipitation to date to be 129% of average, suggesting the amount of water in the snowpack is normal for the amount of precipitation that has fallen this season (no unusual amount of warm or dry or sunny or any other conditions that deplete snowpack compared to average weather conditions). This ratio of SWE to total winter precipitation is about normal in Colorado as a whole, as well.
As mentioned earlier, the South Platte now holds Colorado's' top rank at 111% of average, (114% for precipitation). The Arkansas, which is the only other basin to greatly benefit from last weeks storm, is second at 103%. Otherwise, the state scene is pretty much unchanged from last month. The lowest snowpack is still in the south; the San Juan, Dolores, San Miguel, Animas basins at 75% of average (precip is 80%).
Likewise, the western US is little changed from last month. The most unusual SWE:winter precipitation ratio is still in Alaska which has about 50% of average snowpack, but 110-217% of average total winter precipitation. Montana and Wyoming snowpacks are average or slightly above, and Oregon snowpacks are the lowest at 40-60% of average (however, their winter precipitation amounts are higher). The rest of the states are below average, generally about three quarters of normal. New Mexico is doing better than that with many basins reporting over 100%, and Washington is about 80%. Utah is still surprisingly low (around 75% of average), but its SWE:precip ratio is normal, so it has just received less snow this season so far.
A few words about last weeks storm (March 17-19 or 20): This was a noteworthy event. It has been frequently reported that it was the largest event in 90 years. It brought all movement in the Front Range to a virtual halt for about 3 days, and we are still digging out here at the Mountain Research Station. Snowfall reports in the area range from 5 to 8 feet with SWE's of 5.5 to 8.5 inches. Avalanches along the Eldora ski road stranded skiers at the resort for 2 days, the main highway 119 was not plowed during the hight of the storm, power was out, and roofs collapsed (including the Nederland Community Center roof). (My neighbors finally emerged this past Saturday a week and a half after the storm, thanks to a snow plow. Kathy was down to her last box of Triskets). On Niwot Ridge, my air sampling building, T van, is now completely buried by the following drifts (winds fortunately did not sweep the lower elevations after this storm). The epicenter seems to have been near Rollinsville.
As large as this storm seemed to those experiencing it, the only basins to receive a boost to their snowpack were the South Platte and the Arkansas.
So, Colorado snowpack is is fairly good shape now, but (as the City of Boulder Watershed manager says) "Is the drought over? - NO: Will there be a good runoff this spring? - YES.
Until next month,
The historical manually measured record:
Sno Tel Data Niwot Ridge, C-1
Snow Water Content (inches)
Values are for the end of given month
except as noted for May and June
Season Dec Jan Feb Mar Apr May Jun
81/82 4.75 10.5 11.75 15.5 14.9 12.0 (17th)
82/83 3.63 4.75 12.75 17 11.75 (30th)
83/84 12.6 13.25 15 18.9 20.75
84/85 3.75 6.25 8.5 10.25 8.75
85/86 6.5 7.5 14 15.38 17.5
86/87 6.25 8.75 11.25 12.75 11.75
87/88 6.5 9.1 12.4 15.75 14.5
88/89 5.5 7.6 11 10.25 5.6
89/90 6.5 9.25 10.75 16.1 16.5
90/91 3 5 7.1 9.38 10
91/92 6.65 6.75 8.5 12.25 10.25
92/93 5.75 6.75 10.75 14 15.875
93/94 7.125 9.063 12.25 13.25 13.25 2.5 (18th)
94/95 2.625 3.925 7.0 10.125 16.75 17.0 (22nd) 12.375 (13th)
19.75 (30th)
95/96 7.50 12.00 17.5 20.375 18.75 6.125 (15th)
96/97 8.75 12.625 15.125 14.625 20.375 18.0 (15th)
97/98 7.0625 10.0 10.125 12.875 17.25 12.875 (15th)
98/99 3.25 6.625 8.375 9.125 14.125 14.25 (15th)
99/2000 3.5 7.5 10.625 12.375 7.625
00/2001 4.375 5.375 7.125 10.00 9.125
01/2002 2.625 4.25 6.19 7.563 0.0
02/2003 4.00 5.25 8.5 16.75
Average 5.554 7.967 10.389 13.197 13.363