New 1991-2020 Averages being used this year.
Lake Powell Water Supply Outlook, January 1, 2022

Lake Powell Water Supply Outlook, January 1, 2022

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-July148 195 240 94 295 340
Pine Ck
Fremont Lk, Abv April-July58 70 86 85 95 115
New Fork
Big Piney, Nr April-July145 210 265 75 325 430
Green
Fontenelle Reservoir, Fontenelle, Nr April-July310 535 650 88 775 970
Big Sandy
Farson, Nr April-July20 30 40 80 47 62
Green
Green River, Wy, Nr April-July300 525 650 88 785 1010
Hams Fork
Frontier, Nr, Pole Ck, Blo April-July25 30 43 83 60 70
Viva Naughton Reservoir April-July30 39 55 75 86 105
Blacks Fork
Robertson, Nr April-July56 65 90 102 102 120
Ef Smiths Fork
Stateline Reservoir, Robertson,nr April-July18.5 23 28 100 34 38
Green
Flaming Gorge Reservoir April-July420 650 840 87 1130 1420


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
Stagecoach Rsvr, Abv April-July19.5 23 27 100 31 38
Steamboat Springs April-July155 205 250 96 285 340
Elk
Milner, Nr April-July260 315 395 120 430 470
Elkhead Ck
Long Gulch, Abv, Hayden, Nr April-July55 70 90 127 110 130
Yampa
Maybell, Nr April-July620 800 985 107 1130 1330
Little Snake
Slater, Nr April-July105 125 170 110 200 220
Dixon, Nr April-July195 240 340 103 395 530
Lily, Nr April-July200 250 350 108 430 580
Yampa
Deerlodge Park April-July800 1010 1330 112 1570 1850
White
Meeker, Nr April-July175 200 240 92 280 400
Watson, Nr April-July170 200 245 91 295 430


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-July10 13.5 17 87 20 28
Ashley Ck
Vernal, Nr April-July21 30 40 87 49 70
West Fork Duchesne
Vat Diversion, Blo April-July12 16 20 118 27 35
Duchesne
Tabiona, Nr April-July70 83 110 107 130 155
Rock Ck
Upper Stillwater Reservoir April-July58 68 82 114 102 125
South Fork Rock Ck
Docs Div, Blo April-July4.5 5.5 7.5 103 10 12
Rock Ck
Mountain Home, Nr April-July65 75 96 110 120 145
Currant Ck
Currant Ck Reservoir April-July16 20 25 141 35 45
Strawberry
Strawberry Reservoir, Soldier Springs April-July29 38 60 100 82 105
Starvation Reservoir, Duchesne, Nr April-July65 85 125 133 160 210
Duchesne
Duchesne, Nr, Knight Div, Abv April-July140 170 205 109 250 290
Lake Fork
Moon Lake Reservoir, Mtn Home, Nr April-July45 55 67 105 83 105
Yellowstone
Altonah, Nr April-July45 58 68 113 82 102
Whiterocks
Whiterocks, Nr April-July34 47 56 110 65 90
Uinta
Neola, Nr April-July45 65 80 111 93 123
Duchesne
Myton April-July190 240 345 113 475 575
Randlett, Nr April-July200 255 385 110 525 650


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-July6 9.5 16 127 23 28
Fish Ck
Scofield, Nr, Reservoir, Abv April-July20 25 33 127 42 50
Price
Scofield Reservoir, Scofield, Nr April-July26 35 44 129 58 75
Green
Green River, Ut April-July1730 2230 2950 105 3630 4620
Huntington Ck
Electric Lake April-July10 13 17 150 20 25
Power Plant, Blo April-July35 43 52 130 62 72
Seeley Ck
Joes Vly Reservoir, Orangeville, Nr April-July36 46 54 106 67 80
Ferron Ck
Ferron, Nr April-July25 31 37 106 47 60
Muddy Ck
Emery, Nr April-July12 14.5 17.5 96 24 30


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-July165 195 225 100 250 300
Willow Ck
Willow Ck Reservoir, Granby, Nr April-July30 45 60 120 70 90
Fraser
Winter Park April-July12.5 17 18.5 99 20 23
Williams Fork
Williams Fork Reservoir, Parshall April-July50 70 80 83 92 110
Muddy Ck
Wolford Mountain Reservoir April-July20 32 48 92 55 80
Blue
Dillon Reservoir April-July110 140 160 96 180 210
Green Mtn Reservoir April-July180 235 265 95 315 360
Colorado
Kremmling, Nr April-July550 700 830 95 960 1130
Eagle
Gypsum, Blo April-July210 280 310 93 355 450
Colorado
Dotsero, Nr April-July880 1160 1320 94 1540 1860
Frying Pan
Ruedi Reservoir, Basalt, Nr April-July100 130 140 104 155 190
Roaring Fork
Glenwood Springs April-July515 640 690 105 780 1020
Colorado
Glenwood Springs, Blo April-July1430 1880 2060 99 2370 2940
Cameo, Nr April-July1580 2060 2270 100 2630 3320
Cisco, Nr April-July2700 3500 3900 96 4600 6200
Lake Powell, Glen Cyn Dam, At April-July4000 4900 6300 99 7600 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-July74 87 98 104 113 152
Almont April-July116 136 150 102 170 235
East
Almont April-July150 191 205 116 260 320
Gunnison
Gunnison, Nr April-July275 355 380 109 485 625
Tomichi Ck
Gunnison April-July31 49 58 87 71 109
Lake Fork
Gateview April-July81 92 106 90 115 148
Gunnison
Blue Mesa Reservoir April-July480 570 650 102 770 1030
Morrow Point Reservoir April-July515 610 700 101 840 1100
Crystal Reservoir April-July575 675 770 100 935 1200
Muddy Ck
Paonia Reservoir, Bardine, Nr April-July64 77 90 111 97 162
Nf Gunnison
Somerset, Nr April-July220 255 290 109 325 475
Surface Ck
Cedaredge April-July14.9 18.9 20 137 22 36
Uncompahgre
Ridgway Reservoir April-July62 76 83 90 92 112
Colona April-July75 95 105 88 120 152
Delta April-July30 61 78 72 101 161
Gunnison
Grand Junction, Nr April-July970 1200 1340 101 1660 2250


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-July120 171 205 95 250 385
Mcphee Reservoir April-July141 200 235 92 305 475
San Miguel
Placerville, Nr April-July69 93 106 92 118 149
Dolores
Cisco, Nr April-July240 365 465 92 540 950


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-July131 148 183 94 205 295
Carracas, Nr April-July220 250 310 94 360 555
Navajo Reservoir, Archuleta, Nr April-July375 445 550 87 650 995
Bluff, Nr April-July600 760 900 81 1070 1610
Rio Blanco
Pagosa Springs, Nr, Blanco Dam, Blo April-July33 39 45 92 53 80
Navajo
Chromo, Nr, Oso Div Dam, Blo April-July40 47 54 93 64 95
Little Navajo
Oso Div Dam,bl,chromo,nr April-July2.9 3.9 4.9 80 6.9 11
Piedra
Arboles, Nr April-July90 122 145 80 172 260
Los Pinos
Vallecito Reservoir, Bayfield, Nr April-July116 142 155 88 180 225
Animas
Durango April-July260 320 360 94 415 540
Florida
Lemon Reservoir, Durango, Nr April-July30 35 42 88 51 69
La Plata
Hesperus April-July12.2 17.5 21 91 25 36
Mancos
Mancos, Nr April-July9 13.9 17 98 20 39

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 203.0 102 61 179.9 90 199.0 334.0
untitled Big Sandy
Big Sandy Reservoir, Nr Farson 6.1 38 16 8.0 50 16.1 38.3
Blacks Fork
Meeks Cabin 9.0 88 30 3.2 32 10.2 29.9
untitled Ef Smiths Fork
Stateline Reservoir, Robertson,nr 5.1 94 37 3.6 66 5.4 13.9
untitled Green
Flaming Gorge Reservoir 2899.9 93 77 3156.9 101 3110.9 3749.0
untitled Strawberry
Strawberry Reservoir, Soldier Springs 811.7 100 73 919.4 113 810.6 1105.9
Starvation Reservoir, Duchesne, Nr 125.3 94 76 134.8 101 133.2 165.3
untitled Rock Ck
Upper Stillwater Reservoir 28.7 259 91 9.3 84 11.1 31.4
untitled Lake Fork
Moon Lake Reservoir, Mtn Home, Nr 21.7 122 59 11.0 62 17.7 36.5
untitled Big Brush Ck
Red Fleet Reservoir, Vernal, Nr 9.9 58 39 15.4 90 17.2 25.7
untitled Price
Scofield Reservoir, Scofield, Nr 16.3 67 25 31.4 129 24.2 65.8
untitled Seeley Ck
Joes Vly Reservoir, Orangeville, Nr 21.2 56 34 38.0 101 37.7 62.5
untitled Huntington Ck
Electric Lake 11.4 63 36 19.7 109 18.1 31.5
untitled
TOTAL 4169.3 95 73 4530.7 103 4411.4 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 368.9 94 75 439.8 112 393.0 490.3
untitled Willow Ck
Willow Ck Reservoir, Granby, Nr 6.9 88 76 7.3 94 7.8 9.1
untitled Williams Fork
Williams Fork Reservoir, Parshall 62.5 89 65 72.2 103 69.9 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 31.3 69 47 54.3 119 45.6 66.0
untitled Blue
Dillon Reservoir 196.4 86 77 217.8 96 227.5 254.0
Green Mtn Reservoir 65.0 79 44 74.0 89 82.8 146.9
untitled Homestake Ck
Homestake Reservoir 29.0 90 68 40.3 124 32.4 43.0
untitled Frying Pan
Ruedi Reservoir, Basalt, Nr 58.2 79 57 62.2 84 74.0 102.0
untitled Plateau Ck
Vega Reservoir, Collbran, Nr 5.5 46 17 4.9 41 12.0 32.9
untitled Taylor
Taylor Park Reservoir 58.7 85 55 66.3 96 68.9 106.2
untitled Gunnison
Blue Mesa Reservoir 230.9 43 28 396.8 74 536.0 827.9
Morrow Point Reservoir 105.7 96 90 107.8 98 110.1 117.0
Crystal Reservoir 16.1 106 92 16.5 109 15.1 17.5
untitled Muddy Ck
Paonia Reservoir, Bardine, Nr 0.7 30 4 1.3 57 2.3 16.7
untitled Uncompahgre
Ridgway Reservoir 64.6 96 78 52.9 79 67.0 83.0
untitled Dolores
Mcphee Reservoir 164.8 65 43 167.8 66 255.4 381.1
untitled
TOTAL 1465.3 73 53 1782.3 89 1999.7 2790.6
Colorado
Lake Powell 6713.1 45 28 10130.0 68 14848.1 24322.0
untitled
TOTAL 6713.1 45 28 10130.0 68 14848.1 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 35.2 53 28 35.8 54 66.5 125.4
untitled San Juan
Navajo Reservoir, Archuleta, Nr 871.8 68 51 1079.5 84 1288.2 1696.0
untitled Florida
Lemon Reservoir, Durango, Nr 13.2 74 33 10.6 59 17.9 39.8
untitled
TOTAL 920.3 67 49 1125.8 82 1372.7 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