Niwot Ridge LTER Snow Report for January 2006
Greetings!

The winter snowpack development is well under way at this time, and the La Nina patterns of earlier in the season appear to be solidifying. (The NOAA Climate Prediction Center is forecasting continuing La Nina conditions through the next 3-6 months). Thus, the C1 (Niwot) snowpack is doing well, benefiting from frequent, quasi-daily, snowfalls brought by strong westerly winds blowing over the Continental Divide. This persistent zonal air flow pattern tends to occur more during La Nina conditions at this site, producing snow at the higher elevations, but ironically leaving the lower, eastern plains and metro-Denver, relatively snow-free.

On 31 January 2006, there was 8.375” snow water equivalent (SWE) in 32 inches of snowpack, as measured by hand at C1. This is 107% of the average hand measurements. The Snotel report for this site is concurs, showing 8.2”, or 106% of average. Although this is good news (this January SWE is greater than ever occurred in the 2001/02 season, and it is the highest January SWE since 1998), it is still less than would be expected for the amount of precipitation that has fallen this season. Precipitation to date is 127%, meaning factors detrimental to snowpack development are greater than normal (such as warmer temperatures and greater ablation). This is reflected by a Snowpack Index (SI) of less than one, and only the Arkansas basin has a SI of greater than one in Colorado.

The South Platte Basin is doing well, showing 117% and 124% of average SWE and precipitation, respectively. In Colorado, the highest snowpack is found in the Yampa/White basin at 124% and 129% (SWE and precipitation, respectively), and the Upper Rio Grande has the least snowpack at 46% and 69% (SWE and precip, respectively). The spatial distribution is sharp, with the greatest snowpack in the north and least in the south of Colorado. This pattern is also consistent with La Nina conditions.

The spatial pattern in Colorado reflects that in the western US, where the Great Basin sites of California have the highest snowpack , 134% of average SWE (155% precipitation), edging out Oregon (131% SWE, 133% precipitation). Arizona has the lowest snowpack with 14% (23% precipitation), and New Mexico is the second lowest with 27% (46% precipitation).

Regarding the efficiency of sequestering winter precipitation in the snowpack, the news is not particularly good. Oregon, Washington, and Utah are the only states with an SI of greater than one, and only two of the seven major river basins have a SI greater than one, the Missouri and Columbia. The lower Colorado River basin has only 20% SWE (31% precip), and the upper portion of this basin is just over average with 107% SWE (110% precip).

Until next month, cheers!

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   10.125    3.69 (14th)
      04/2005  4.875    7.7       9.5     11.625   12.875   12.25 (15th)
      05/2006  5.625    8.375 

     Average   5.418    7.842    10.242   12.908   13.25