Lake Powell Water Supply Outlook, February 1, 2023

Note: This publication is scheduled for revision. If you have feedback on content, format, or publication frequency, please contact us.
Prepared by Ashley Nielson
NOAA, National Weather Service
Colorado Basin River Forecast Center
Salt Lake City, Utah
www.cbrfc.noaa.gov

Contents

Lake Powell Sub-Basin Summaries




*Median of forecasts within each basin.





*Median of forecasts within each basin.







*Median of forecasts within each basin.




Upper Green Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Yampa/White Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Duchesne Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Lower Green Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Upper Colorado Mainstem Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Gunnison Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Dolores Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

San Juan Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.


Upper Green Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
Green
Daniel, Nr, Warren Bridge, At April-July145 185 220 86 250 315
Pine Ck
Fremont Lk, Abv April-July69 78 88 87 98 115
New Fork
Big Piney, Nr April-July205 265 315 89 385 435
Green
Fontenelle Reservoir, Fontenelle, Nr April-July400 550 650 88 800 995
Big Sandy
Farson, Nr April-July31 42 50 100 58 70
Green
Green River, Wy, Nr April-July400 550 650 88 850 1020
Hams Fork
Frontier, Nr, Pole Ck, Blo April-July35 45 55 106 70 85
Viva Naughton Reservoir April-July47 60 75 103 105 130
Blacks Fork
Robertson, Nr April-July68 77 88 100 105 120
Ef Smiths Fork
Stateline Reservoir, Robertson,nr April-July22 25 28 100 34 38
Green
Flaming Gorge Reservoir April-July580 745 880 91 1270 1500


Yampa/White Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
Yampa
Steamboat Springs April-July260 300 325 125 365 430
Elk
Milner, Nr April-July370 405 455 138 500 575
Elkhead Ck
Long Gulch, Abv, Hayden, Nr April-July85 100 120 169 135 155
Yampa
Maybell, Nr April-July950 1090 1250 136 1430 1650
Little Snake
Slater, Nr April-July155 170 195 126 230 250
Lily, Nr April-July345 395 450 138 560 650
Yampa
Deerlodge Park April-July1290 1480 1700 143 2000 2200
White
Meeker, Nr April-July275 300 330 127 375 490
Watson, Nr April-July285 325 355 131 410 560


Duchesne Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
Big Brush Ck
Vernal, Nr, Red Fleet Res, Abv April-July15 20 23 117 28 34
Ashley Ck
Vernal, Nr April-July35 45 55 120 65 82
West Fork Duchesne
Vat Diversion, Blo April-July17 22 25 147 28 35
Duchesne
Tabiona, Nr April-July95 107 120 117 135 163
Rock Ck
Upper Stillwater Reservoir April-July65 72 80 111 98 125
South Fork Rock Ck
Docs Div, Blo April-July6.4 7.5 8.5 116 10 12.2
Rock Ck
Mountain Home, Nr April-July80 90 100 115 120 150
Currant Ck
Currant Ck Reservoir April-July18 22 28 158 33 42
Strawberry
Strawberry Reservoir, Soldier Springs April-July44 60 70 117 88 105
Starvation Reservoir, Duchesne, Nr April-July75 103 125 133 155 210
Duchesne
Duchesne, Nr, Knight Div, Abv April-July175 200 220 117 250 310
Lake Fork
Moon Lake Reservoir, Mtn Home, Nr April-July54 60 70 109 80 107
Yellowstone
Altonah, Nr April-July50 60 70 117 80 103
Whiterocks
Whiterocks, Nr April-July40 50 65 127 75 91
Uinta
Neola, Nr April-July57 75 90 125 100 130
Duchesne
Myton April-July240 310 370 121 470 650
Randlett, Nr April-July270 350 440 126 530 770


Lower Green Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
White
Blo Tabbyune Ck, Soldier Summit, Nr April-July12 16 21 167 25 32
Fish Ck
Scofield, Nr, Reservoir, Abv April-July32 38 45 173 50 60
Price
Scofield Reservoir, Scofield, Nr April-July42 50 60 176 70 90
Green
Green River, Ut April-July2500 3000 3500 125 4300 5400
Huntington Ck
Electric Lake April-July15 17.5 20 177 23 27
Power Plant, Blo April-July45 50 55 138 63 78
Seeley Ck
Joes Vly Reservoir, Orangeville, Nr April-July50 58 64 125 70 87
Ferron Ck
Ferron, Nr April-July32 36 41 117 47 60
Muddy Ck
Emery, Nr April-July15 18 21 115 25 32


Upper Colorado Mainstem Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
Colorado
Lake Granby, Granby, Nr April-July175 205 230 102 255 300
Willow Ck
Willow Ck Reservoir, Granby, Nr April-July38 54 64 128 76 96
Fraser
Winter Park April-July15 17.5 20 108 22 25
Williams Fork
Williams Fork Reservoir, Parshall April-July65 78 90 94 100 120
Muddy Ck
Wolford Mountain Reservoir April-July35 48 60 115 70 90
Blue
Dillon Reservoir April-July115 140 160 96 180 210
Green Mtn Reservoir April-July190 240 270 96 305 360
Colorado
Kremmling, Nr April-July640 780 900 103 1030 1250
Eagle
Gypsum, Blo April-July225 280 320 96 370 460
Colorado
Dotsero, Nr April-July1080 1280 1460 104 1640 2020
Frying Pan
Ruedi Reservoir, Basalt, Nr April-July95 118 132 98 148 180
Roaring Fork
Glenwood Springs April-July550 620 700 107 780 950
Colorado
Glenwood Springs, Blo April-July1660 1950 2180 105 2400 3020
Cameo, Nr April-July1900 2200 2450 108 2800 3450
Cisco, Nr April-July3550 4150 4550 112 5200 6550
Lake Powell, Glen Cyn Dam, At April-July5500 6600 7500 117 8500 11000


Gunnison Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
Taylor
Taylor Park Reservoir April-July82 92 105 112 113 149
Almont April-July128 145 163 111 176 245
East
Almont April-July153 180 200 113 220 280
Gunnison
Gunnison, Nr April-July305 355 400 114 430 585
Tomichi Ck
Gunnison April-July35 49 60 90 73 107
Lake Fork
Gateview April-July88 100 114 97 120 156
Gunnison
Blue Mesa Reservoir April-July500 610 680 107 730 960
Morrow Point Reservoir April-July540 655 730 106 785 1020
Crystal Reservoir April-July610 725 815 106 880 1130
Muddy Ck
Paonia Reservoir, Bardine, Nr April-July74 92 102 126 111 155
Nf Gunnison
Somerset, Nr April-July245 290 315 119 335 455
Surface Ck
Cedaredge April-July15.9 18.9 21 144 24 31
Uncompahgre
Ridgway Reservoir April-July73 88 94 102 101 126
Colona April-July88 112 124 103 129 171
Delta April-July73 90 99 104 113 156
Gunnison
Grand Junction, Nr April-July1160 1340 1470 111 1580 2100


Dolores Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
Dolores
Dolores April-July180 230 265 123 300 365
Mcphee Reservoir April-July205 265 315 124 360 440
San Miguel
Placerville, Nr April-July83 107 120 104 132 160
Dolores
Cisco, Nr April-July395 530 600 119 695 900


San Juan Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
San Juan
Pagosa Springs April-July150 177 200 103 225 270
Carracas, Nr April-July245 290 330 100 380 455
Navajo Reservoir, Archuleta, Nr April-July445 540 620 98 725 900
Bluff, Nr April-July705 880 1050 95 1210 1440
Rio Blanco
Pagosa Springs, Nr, Blanco Dam, Blo April-July35 42 48 98 56 67
Navajo
Chromo, Nr, Oso Div Dam, Blo April-July43 51 58 100 66 84
Little Navajo
Oso Div Dam,bl,chromo,nr April-July3.7 4.7 5.8 95 6.6 9.9
Piedra
Arboles, Nr April-July122 148 180 99 200 250
Los Pinos
Vallecito Reservoir, Bayfield, Nr April-July150 173 190 107 205 255
Animas
Durango April-July325 385 425 110 480 570
Florida
Lemon Reservoir, Durango, Nr April-July40 48 55 115 62 75
La Plata
Hesperus April-July16.6 20 23 100 26 35
Mancos
Mancos, Nr April-July13.6 17.2 21 122 25 37

Differences between the full period forecasts and the residual forecasts may not exactly equal the actual observed volumes due to rounding conventions (see Definitions section).

Green End of Month Reservoir Contents (kaf)

EOM
Contents		Percent
EOM
Average		Percent
Usable
Capacity		Last Year
EOM		Last Year
%Average		EOM
Average		Usable
Capacity
untitled Green
Fontenelle Reservoir, Fontenelle, Nr 166.8 101 50 180.2 109 165.5 334.0
untitled Big Sandy
Big Sandy Reservoir, Nr Farson 7.5 44 20 6.5 38 16.9 38.3
Blacks Fork
Meeks Cabin 9.5 83 32 10.5 92 11.4 29.9
untitled Ef Smiths Fork
Stateline Reservoir, Robertson,nr 6.1 110 44 5.5 100 5.5 13.9
untitled Green
Flaming Gorge Reservoir 2496.9 81 67 2900.9 94 3081.2 3749.0
untitled Strawberry
Strawberry Reservoir, Soldier Springs 810.1 100 73 829.0 102 811.3 1105.9
Starvation Reservoir, Duchesne, Nr 131.6 94 80 133.7 96 139.7 165.3
untitled Rock Ck
Upper Stillwater Reservoir 9.1 90 29 13.4 132 10.1 31.4
untitled Lake Fork
Moon Lake Reservoir, Mtn Home, Nr 25.5 128 70 23.8 120 19.9 36.5
untitled Big Brush Ck
Red Fleet Reservoir, Vernal, Nr 9.7 55 38 10.6 60 17.7 25.7
untitled Price
Scofield Reservoir, Scofield, Nr 14.4 56 22 17.8 70 25.6 65.8
untitled Seeley Ck
Joes Vly Reservoir, Orangeville, Nr 30.1 78 48 21.5 56 38.5 62.5
untitled Huntington Ck
Electric Lake 10.8 61 34 11.1 63 17.6 31.5
untitled
TOTAL 3728.0 85 66 4164.4 95 4360.8 5689.6


Upper Colorado End of Month Reservoir Contents (kaf)

EOM
Contents		Percent
EOM
Average		Percent
Usable
Capacity		Last Year
EOM		Last Year
%Average		EOM
Average		Usable
Capacity
untitled Colorado
Lake Granby, Granby, Nr 452.2 123 92 340.5 93 367.8 490.3
untitled Willow Ck
Willow Ck Reservoir, Granby, Nr 8.0 97 88 7.5 91 8.3 9.1
untitled Williams Fork
Williams Fork Reservoir, Parshall 43.3 63 45 60.5 88 68.4 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 39.8 88 60 30.9 68 45.1 66.0
untitled Blue
Dillon Reservoir 207.9 93 82 196.3 88 224.2 254.0
Green Mtn Reservoir 79.6 104 54 59.6 78 76.5 146.9
untitled Homestake Ck
Homestake Reservoir 29.8 94 69 28.8 91 31.8 43.0
untitled Frying Pan
Ruedi Reservoir, Basalt, Nr 65.0 92 64 57.7 82 70.8 102.0
untitled Plateau Ck
Vega Reservoir, Collbran, Nr 9.8 78 30 5.7 45 12.6 32.9
untitled Taylor
Taylor Park Reservoir 65.4 96 62 58.3 86 68.1 106.2
untitled Gunnison
Blue Mesa Reservoir 295.4 57 36 236.4 46 515.2 827.9
Morrow Point Reservoir 104.5 95 89 104.7 95 109.9 117.0
Crystal Reservoir 16.5 110 94 16.2 108 15.0 17.5
untitled Muddy Ck
Paonia Reservoir, Bardine, Nr 1.2 45 7 0.5 21 2.6 16.7
untitled Uncompahgre
Ridgway Reservoir 69.3 103 83 65.1 96 67.5 83.0
untitled Dolores
Mcphee Reservoir 189.1 74 50 166.7 65 256.3 381.1
untitled
TOTAL 1676.7 86 60 1435.5 74 1940.2 2790.6
Colorado
Lake Powell 5456.1 38 22 6335.2 44 14430.3 24322.0
untitled
TOTAL 5456.1 38 22 6335.2 44 14430.3 24322.0


San Juan End of Month Reservoir Contents (kaf)

EOM
Contents		Percent
EOM
Average		Percent
Usable
Capacity		Last Year
EOM		Last Year
%Average		EOM
Average		Usable
Capacity
untitled Los Pinos
Vallecito Reservoir, Bayfield, Nr 71.8 105 57 38.6 56 68.5 125.4
untitled San Juan
Navajo Reservoir, Archuleta, Nr 847.1 66 50 859.1 67 1277.0 1696.0
untitled Florida
Lemon Reservoir, Durango, Nr 17.0 94 43 13.2 73 18.1 39.8
untitled
TOTAL 935.9 69 50 910.9 67 1363.6 1861.2

Precipitation Maps




Definitions

10% exceedance forecast: Given the current hydrometeorological conditions, i.e current snowpack, soil moisture and streamflow, the volume that has a 10% chance of being exceeded. Previously referred to as "Reasonable Maximum Forecast".

50% exceedance forecast: Given the current hydrometeorological conditions, i.e current snowpack, soil moisture and streamflow, the volume that has a 50% chance of being exceeded. Previously referred to as "Most Probable Forecast".

90% exceedance forecast: Given the current hydrometeorological conditions, i.e current snowpack, soil moisture and streamflow, the volume that has a 90% chance of being exceeded. Previously referred to as "Reasonable Minimum Forecast".

Acre-Foot (af): The volume equal to one acre covered one foot deep (43,560 cubic feet). See kaf below.

Average: The arithmetic mean. The sum of the values divided by the number of values. Values from 1991-2020 are used for this publication.

Categories: Much Above Average=Greater than 130%, Above Average=111-130%, Near Average=90-110%, Below Average=70-89%, Much Below Average=Less than 70%.

CBRFC: Colorado Basin River Forecast Center.

Forecast Period: The period from April 1 through July 31, unless otherwise noted.

kaf: Thousand Acre-Feet. See Acre-Foot above.

Inflow: The volume of water that flows into a reservoir or lake.

Median: The middle value of an ordered set of values. Half of the values are higher and half of the values are lower. When the set contains an even number of values the median is the average of the two middle numbers.

NOAA: National Oceanic and Atomospheric Administration.

NWS: National Weather Service.

Rounding Conventions:
RangeRound to
0-1.990.01
2.0-19.90.1
20-1991.0
200-9995.0
1000+3 significant digits


Streamflow: The volume of water that flows past a specific stream site.

Water Year: The 12-month period, October 1 through September 30. The water year is designated by the calendar year in which it ends. Thus, the year ending September 30, 2008, is called the "2008 water year."


Additional Information

Water supply forecasts take into consideration present hydrometeorological conditions and use average basin temperatures and precipitation for the forecast period. As the forecast season progresses, a greater portion of the future hydrologic and climatic uncertainty becomes known and monthly forecasts become more accurate. For more information on the tools we use, consult Water Supply Forecasting Tools.

Volume forecasts represent adjusted flows; that is, observed flows with upstream water use taken into account. Adjusted flows will closely approximate natural or unimpaired flows. However, not all upstream diversions or impoundments are measured or quantifiable. For specific adjustments used with each forecast point, consult the Guide to Water Supply Forecasting.

The Water Supply Outlook is issued monthly January through May by the Colorado Basin River Forecast Center. It represents a coordinated effort between the National Weather Service, Natural Resources Conservation Service, Bureau of Reclamation, U.S. Geological Survey and local water district managers.

Note: Data used in this report are provisional and are subject to revision.

For more information, or to be included on the mailing list, please contact:

Colorado Basin River Forecast Center
2242 W North Temple
Salt Lake City, UT 84116
(801) 524-5130
www.cbrfc.noaa.gov