Greetings from Niwot Ridge!

The February snowpack here at C1 dropped a bit from last month, percentage-wise, but is 
still the highest end-of-February value since 1998.
On 28 February 2005, the snow water equivalent (SWE) at C1 was 9.5 inches, or 92% of 
average, as measured by hand today.  This compares to the Snotel value of 8.8", or 90% 
of average.  The Snotel cumulative winter precipitation at C1 is 11.7", or 107% of 
average, indicating negative weather conditions that promote snowpack development 
relative to the long term (warmer, drier winds, etc.  The Snowpack Index (SI) of less than 
one is another way of say this.

Statewide, the pattern begun at the start of the season is continuing: slightly below 
average in the northern and eastern basins, and well above average in the southern and 
southwestern basins, giving a statewide average of 112% (104% winter precip).  Our 
South Platte basin has the lowest snowpack, on a percentage basis, at 84%, and a 
cumulative winter precipitation of 85% (SI essentially 1, or normal).  The other northern 
and eastern basins show similar snowpack levels; 88% and 89% for the Yampa/White, 
and Laramie/N.Platte, respectively.  
The San Miguel/San Juan/Animas/Dolores basin has the highest snowpack at 152% 
(127% cumulative winter precipitation), with the Upper Rio Grande essentially the same 
(151% and 136%, snow/winter precip, respectively).

 Colorado continues to be a microcosm of the western US; wetter southern and drier 
northern regions, and the SI tends to be less than one in the drier regions and greater than 
one in the wetter ones.
The state of Washington continues to have the lowest snowpack in the western US, 
reporting only 27% of average (64% winter precip), and Oregon is little better with 37% 
and 56%, snowpack/winter precip, respectively.
Arizona, Utah,  the Great Basin sites of California, and New Mexico again have the 
highest snowpacks: 163%, 141%, 134%, and 132%, respectively, and their SI's are 
greater than one.

Two comments on current snowpack conditions:
1.)  The low snowpacks in the Pacific Northwest, where winter temperatures are closer to 
the freezing level, are consistent with recent predictions of Mote, et al (BAMS vol.86, no. 
1, Jan 2005), that such regions will be most susceptible to warming climate conditions. 
Note that the low snowpack here is well below expected, given their cumulative winter 
precipitation.

2.) This strong El Nino pattern of winter precipitation is unusual given the sea surface 
temperatures indicating only a very weak El Nino.  In fact, NOAA's Climate Prediction 
Center forecasts the next three months to transition from current weak El Nino to ENSO-
neutral conditions (10 Feb report).  
There is a hypothesis that El Nino, or La Nina, conditions will be as expected when 
ENSO and the PDO (Pacific Decadal Oscillation) are in phase, but not when they are out 
of phase with each other.  There is speculation the the PDO is shifting phase right now 
(but years are often needed to know for sure), which would make it out of phase with 
ENSO and this current weak El Nino.

Until next month,
Mark Losleben

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

     Average   5.409    7.819    10.242   12.964   13.266