Current Theme: Waterworks
	Snowpack report - Niwot Ridge - March, 2004 Mark Losleben - CU INSTAAR Research Staff

The following snowpack conditions on Niwot Ridge have been reported by Mark Losleben for March 2004. Select here for more information about these snowpack reports

Greetings!

This report of March snowpack conditions at C1 (Niwot), and general comments on the western US, comes during what appears to be the start of summer. Virtually all areas have suffered severe declines in snowpack, and here we have lost virtually all snowpack at elevations below 9,000.

The manual measurements of snowpack at the Niwot, C1 site on 31 March 2004 show it to be 21 inches deep, contain 7.875" of water (SWE), which is 60% of average, and have a density of 39%. This is the second lowest SWE in 23 years (2002 had 7.563"), and is a decline from 75% of average last month.

The NRCS Snotel reports Niwot to have 6.9" SWE, for 56% of average compared to 72% of average last month, and the South Platte basin to have 61% SWE and 67% of cummulative winter precipitation. Last month those values were 68%/70% respectively. In Colorado, the Upper Rio Grande still has the highest snowpack, on a percentage basis, with 83%/93% (SWE/cummulative winter precipitation), but this is a decline from 108%/103% last month. The S. Platte still takes the lowest basin award (61%/67%). In the western US, all states snowpack declined, but the most in Arizona and New Mexico (currently at 8% and 46% of average SWE, respectively). The least decline was in the Pacific Northwest, particularly the Oregon Cascades which are at near normal levels. This is also the first time this season that the Snowpack Index was below one in every state except Oregon. (This means less moisture is stored for release from snowpacks thoughout the summer, than on average).

More perspective at our local site: the C1 snowpack at this time of year, is very close to that in 2002, and not far from what it would have been last year had not the "mega" snow storm occurred. We recieved 2.00" SWE this March, 10.19" last year (and about 9" of that was in the "mega" storm). Prior March total SWE's were 2.63", 3.74", 3.11", and 1.95" for the years 2002 through 1999, respectively. Without a major turnaround in relative conditions, the peak snowpack will have occurred 10 days earlier this year, than the previous record in 2002. This is 1.96 standard deviations earlier than the 23 year mean peak date.

Interestingly though, there is absolutely no statstically significant trend in peak snowpack amount, date of peak, date of melt-out, rate of melt-out, or the number of days from peak accummulation to melt-out over the past 23 years.

So, there are also several other reasons to hope that the snow accummulation season is not over yet. Klaus Wolter has found that a wet April tends to follow a dry March (but not always!). Also, 50% of the time the C1 snowpack SWE is higher at the end of April compared to March (n=23), and the medium range forecasts are predicting mostly wet conditions for Colorado starting tomorrow, continuing for at least a week.

So, while it is dry right now, the fire season has already started, and it appears there will be insufficient stream flows to fill reservoirs right now, there is hope! With weather, each day can bring surprises, and especially here in the spring!

Until next month,

Mark

                      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    14.375   11.44 (15th)
      03/2004  2.75     4.813     7.75     7.875

     Average   5.432    7.824    10.274   12.964   13.409