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

Wyoming Water Availability January 2006

Source: Wyoming Water Resources Data System and USDA Natural Resources Conservation Service

The current SWE as a percent of average varies
across the state of Wyoming as of January 4,2006
(Figure 8a). The south-central mountains and the
western mountains generally have above average
snowpack levels, ranging from 100% - 160% of
average SWE. The central mountains bordering the
Big Horn and Po\vder River basins only have be-
tween 40% - 120% of average SWE. Some stations
in the Shoshone and Wind River basins have less
than 60% of average SWE.
The Surface Water Supply Index (SWSI) varies
across the state of Wyoming as if January 1, 2006.
The Upper Snake and Big Sandy River basins in the
west are the driest with moderate drought conditions.
Other basins facing a mild drought include the Wind,
the Big Horn, and the Po\vder, River basins. The
wettest basin is the Upper North Platte basin, which
is between slightly and moderately wet.

Notes
Figure 8a shows the SWE as
a percent of average for each
of the major river basins in
Wyoming. According to the
WY NRCS, "The Surface Water
Supply Index (SWSI-Figure 8b)
is computed using only surface
water supplies for the drainage.
The computation includes reser-
voir storage, if applicable, plus
the forecast runoff. The index is
purposely created to resemble
the Palmer Drought Index, with
normal conditions centered near
zero. Adequate and excessive
supply has a positive number
and deficit water supply has a
negative value. Soil moisture
and forecast precipitation are
not considered as such, but the
forecast runoff may consider
these values."

- ~ 1

Upper
Snake
-2.44

1 "---' . ~
\....
) Upper Gr" n
-0.03,

lL .Iii. ~ -:: !'! .~'-

'~ ~ .~' ~it "
,~ .. a ij. ~~_

. . q . =ti ./L ~rj' ~-
C u rrelilt Sn,ow fl.r:1L w.~ . iv
WaIter Equiv. J.~. \v : Gody.~
% of INo~rma,',1 rl'~ f~ ~ 11 ~
.IIi. ~-=f ~
" missin.g;'; ~ 1'lii1' A
..L._ (I' ..Ii.. if ~.& \ yo -
- g- -... .Ii. . i;j
, ~~. .~\ l'
.. ~ ,!f..,
--. \....... _'I

..... ..............
!,

,. 0-400
yo -40--6(1
"t;' 60-80
..,. aO-101l
.IJ. 1 00'- iI ~)

.4 12(1....040
a 140.. ilOO
.& > 160

I

Figure 8a. Currrent snow water equivalent (SWE) as a percent
of normal for SNOTEL sites in Wyoming as of January 4, 2006.
This is orovisional data. For current SNOTEL data and plots
of specific sites, see http://www.wcc.nrcs.usda.gov/snow/.

Shoshone
0_42

.Powder

-0_ 93

J
1

-0.96

J ~.

I Big -Horn
.. 1
-'11

-1.32

Legend

> 4.0 Extremely Wet
3.0 Very Wet
2.0 Moderately Wet
1.0 Slightly Wet
0.5 Incipient Wet Spell
0.0 Near Normal
- 0.5 Incipient Dry Spell
- 1.0 Mild Drought
- 2.0 Moderate Drought
- 3.0 Severe Drought
< - 4.0 Extreme Drought

Figure 8b. Wyoming Surface Water Supply Index (released 1/06/06)

Lower Northr
I
( {
-0_ 03 ,
LaiiJ ~
I

On the Web
- Information on current Wyoming snowpack, SWE, and SWSI, along with more data about current water supply status
for the state, can be found at: http://www.wrds.uwyo.edu/wrds/nrcs/nrcs.html.
- The Palmer Drought Index is found on NOAA's drought page: www.drought.noaa.gov.
- For current streamflow information from USGS, visit: http://water.usgs.gov/waterwatch/

RECENT CONDITIONS 111