IntermtnClimateSummaryJan2006

• Title: Intermountain West Climate Summary
• Date: 1/17/2006
• Description: Water Availability Task Force Meeting Presentation
• Basin: Statewide
• Drought Mitigation - Doc Type: Presentation

INTERMOUNTAIN WEST CLIMATE SUMMARY, JANUARY 2006

Colorado Water Availability January 2006

Source: USDA Natural Resources Conservation Service

The percent of average SWE in Colorado varies
throughout the state as of January 4, 2006 (Figure
7a). The mountains surrounding the Rio Grande Riv-
er basin have 60% to less than 40% of normal SWE.
On the other hand, the northern mountains along the
continental divide have had considerable snow since
October and they range from 100 % to above 160%
of normal snowpack.
The Surface Water Supply Index (SWSI) is an-
other useful measure of water availability related to
streamflows, reservoir levels, and ground\vater levels.
Like the SWE map, the Colorado SWSI map shows
more water supplies in the north and less in the south.
The Dolores/San Juan and Rio Grande basins are in
drought categories, with the Rio Grande approaching
severe drought. The rest of the state is either near
or above normal. The Arkansas and Colorado River
basins are approaching abundant supply. In a CBS4
online news story from January 6, 2006, State clima-
tologist, Roger Pielke Sr., noted that the southern part
of the state is facing conditions comparable to the
drought of 2002.

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Figure 7a. Currrent snow water equivalent (SWE) as a percent
of normal for SNOTEL sites in Colorado as of January 4, 2006.
This is orovisional data. For current SNOTEL data and plots
of specific sites, see http://www.cbrfc.noaa.gov/snow/snow.cgi
or http://www.wcc.nrcs.usda.gov/snow/.

SURFACE WATER SUPPLY INDEX
January 1, 2006

--------------- Majo r Rivers
~ Basin Boundary

I x. X I SWSI Number

Abundant Supply

Near Normal

Mod erate D ro ug ht

Severe D ro ught

Extreme Drought

Figure 7b. Colorado Surface Water Supply Index. The map shows the projected
water availability by basin for spring and summer 2006, based on current conditions
as of January 1. (released 1/10/06)

Notes
Figure 7a shows the SWE as a percent
of normal (average) for SNOTEL sites
in Colorado. Figure 7b shows the
Surface Water Supply Index (SWSI),
developed by the Colorado Office of the
State Engineer and the USDA Natural
Resources Conservation Service. SWSI
is used as an indicator of mountain-
based water supply conditions in the
major river basins of the state and is
based on snowpack, reservoir storage,
and precipitation for the winter period
(November through April). During the
winter period, snowpack is the primary
SWSI component in all basins except
the South Platte Basin where reservoir
storage is given the most weight. The
SWSI values in Figure 7b were com-
puted for each of the seven major basins
in Colorado for January 1 , 2006, and
reflect conditions during the month of
December 2005.

On the Web
- For current maps of SWE as a percent of normal like in Figure 7a, go to: http://www.wcc.nrcs.usda.gov/gis/snow.html.
- For the current SWSI map, go to: http://www.co.nrcs.usda.gov/snow/fcst/state/current/monthly/maps_graphs/index.html.
- For current streamflow information from USGS, visit: http://water.usgs.gov/waterwatch/.

RECENT CONDITIONS 110