March 1, 2021 Spring and Summer Streamflow Forecasts
Upper Missouri Basin
The high elevation snow pack in the Upper Missouri Basin as of March 1
was near to above average. The snow pack in the St. Mary Basin was 103 percent, and the
Milk River Basin was 115 percent.
February precipitation across the Upper Missouri Basin was near to above average.
Basin precipitation summaries for the Missouri Basin include: Milk St. Mary,
79 percent; Milk Canada, 93 percent; Lower Milk, 78 percent; above Toston,
172 percent; Toston to Ft. Peck, 167 percent.
February 2021 Upper Missouri Mean Precip Oct-Feb WY2021 Upper Missouri Mean Precip
Stream flow in the Upper Missouri Basin is forecast to be
below average during the upcoming Spring and Summer.
The St. Mary River is forecast to have 75 percent of average
April-September flows. Runoff is expected to range around
93 percent of average for the Missouri Basin above Fort Peck,
Montana.
Upper Missouri March 1, 2021 Spring and Summer Streamflow Forecasts
Of the four major irrigation reservoirs in Montana; Lima
Reservoir had 133 percent average storage, Clark Canyon was
holding 106 percent of average water, Gibson Reservoir had 69
percent of average stored water, and Fresno Reservoir had
65 percent of average stored water.
Yellowstone Basin
The high elevation snow pack in the Yellowstone Basin was near average
on March 1. The snow pack in the Upper Yellowstone Basin was 110 percent
of average. The snow packs in the Wind, Bighorn, and Shoshone Basins were 79,
94, and 111 percent of average, respectively. The snow packs in the Tongue
and Powder basins were 99 and 98 percent of average, respectively.
Precipitation during February was above average. The upper Yellowstone
River Basin received 198 percent of average precipitation while the
Lower Yellowstone River Basin reported 144 percent of average. The
Bighorn Basin received 245 percent of average precipitation while the
Wind River Basin received 120 percent of average. The Little Bighorn -
Upper Tongue Basin received 175 percent of average and the Powder River
had 124 percent of average precipitation.
February 2021 Yellowstone Mean Precip Oct-Feb WY2021 Yellowstone Mean Precip
Forecast stream flow in the Yellowstone Basin is below average
for the upcoming Spring and Summer. Stream flow for the
Yellowstone River above Sidney, Montana is forecast to be about
88 percent of average. Flow in the Tongue Basin is expected to be
72 percent of average. Flows in the Powder River are expected
to be about 58 percent of average.
Monthend storage at Boysen Reservoir was 103 percent of average.
Stored water in Buffalo Bill Reservoir was 129 percent of average.
Monthend storage was 103 percent of average at Bighorn Reservoir.
Yellowstone March 1, 2021 Spring and Summer Streamflow Forecasts
Platte Basin
The high elevation snow pack in the Upper North Platte Basin was
93 percent of average on March 1. The snow pack in the North Platte
Basin below Seminoe Reservoir was 91 percent of average. The snow
pack in the South Platte Basin was 90 percent of average.
Precipitation during February in the Upper North Platte Basin was 132
percent of average. In the Lower North Platte Basin, precipitation
was 99 percent of average. The North Platte Plains below Guernsy
Reservoir had 155 percent. The South Platte Mountains had 143
percent whereas the Plains had 169 percent of average December
precipitation.
DecemberFebruary 2021 Platte Mean Precip Oct-Feb WY2021 Platte Mean Precip
Stream flow in the Platte Basin is forecast to be below
average during the upcoming Spring and Summer. Runoff
for streams above Seminoe Reservoir are expected to be
about 75 percent of average. Streams in the South Platte
Basin above South Platte, Colorado can expect 68 percent
of average flow. For the remainder of the South Platte
basin, flows are expected near 64 percent.
Stored water in the South Platte Basin was 93 percent of average
on March 1.
North Platte Streamflow Fcst South Platte Streamflow Fcst
FGUS63 KKRF 021337
ESPKRF
WATER SUPPLY FORECAST
NWS MISSOURI BASIN RIVER FORECAST CENTER
PLEASANT HILL MISSOURI
*** UPDATED VERSION WITH ALL FORECAST LOCATIONS ***
0728 AM CST TUESDAY MARCH 02, 2021
DATA CURRENT AS OF: MARCH 01, 2021
MISSOURI/YELLOWSTONE/PLATTE RIVER BASIN FORECASTS
50% % 10% 90% AVG
FORECAST POINT PERIOD (KAF) AVG (KAF) (KAF) (KAF)
--------------------------------------------------------------------
Boysen Resvr Inflow Apr-Sep 676 59 1177 416 1140
SBDW4N
Bighorn R at Kane Apr-Sep 1051 62 1768 660 1690
LVEW4N
Greybull R at Meeteetse Apr-Sep 116 65 211 58 177
MEEW4N
Buffalo Bill Resvr Inflow Apr-Sep 533 70 733 408 765
CDYW4N
St. Mary R nr Babb Apr-Sep 420 79 482 357 535
SMYM8N
St. Mary R at Intl Boundary Apr-Sep 492 75 578 413 660
SMBM8N
Milk R nr Western Crossing Apr-Sep 27 67 58 14 41
PDBM8N
Milk R nr Eastern Crossing Apr-Sep 44 55 109 22 81
ERNM8N
North Platte R nr Northgate Apr-Sep 162 54 314 81 300
NGTC2
Encampment R nr Encampment Apr-Sep 91 60 137 57 150
ECRW4
Encampment R nr Encampment Apr-Sep 100 62 146 66 160
ECRW4N
Rock Cr nr Arlington Apr-Sep 46 88 61 34 52
KCRW4
Rock Cr nr Arlington Apr-Sep 46 87 61 34 53
KCRW4N
Seminoe Resvr Inflow Apr-Sep 418 52 798 221 805
SETW4
Seminoe Resvr Inflow Apr-Sep 559 59 942 351 955
SETW4N
Laramie R nr Woods Landing Apr-Sep 24 23 75 13 108
WODW4
Laramie R nr Woods Landing Apr-Sep 58 41 111 39 142
WODW4N
Little Laramie R nr Filmore Apr-Sep 50 91 78 36 55
SMTW4
Little Laramie R nr Filmore Apr-Sep 52 91 80 38 57
SMTW4N
Antero Resvr Inflow Apr-Sep 14 83 22 10 17
ANRC2N
Spinney Mountain Resvr Inflow Apr-Sep 33 58 58 21 56
SPYC2N
Elevenmile Canyon Resvr Inflow Apr-Sep 35 59 64 23 60
EVNC2N
Cheesman Lk Inflow Apr-Sep 68 60 130 44 114
CHEC2N
S Platte R at S Platte Apr-Sep 125 61 227 81 205
SPTC2N
Bear Cr at Morrison Apr-Sep 9 45 22 6 21
MRRC2N
Clear Cr at Golden Apr-Sep 55 47 92 37 117
GLDC2N
St. Vrain Cr at Lyons Apr-Sep 67 60 107 50 111
LNSC2N
Boulder Cr nr Orodell Apr-Sep 38 72 54 26 52
OROC2N
S Boulder Cr nr Eldorado Sprgs Apr-Sep 20 51 34 10 40
BELC2N
Cache La Poudre at Canyon Mouth Apr-Sep 138 66 247 78 210
FTDC2N
Lima Resvr Inflow Apr-Sep 45 58 72 27 78
LRRM8N
Clark Canyon Resvr Inflow Apr-Sep 91 58 141 58 159
CLKM8N
Beaverhead R at Barretts Apr-Sep 121 62 177 85 194
BARM8N
Ruby R Resvr Inflow Apr-Sep 82 84 100 61 97
ALRM8N
Big Hole R nr Melrose Apr-Sep 517 92 787 390 560
MLRM8
Big Hole R nr Melrose Apr-Sep 576 101 844 448 570
MLRM8N
Hebgen Resvr Inflow Apr-Sep 426 99 499 364 430
HBDM8N
Ennis Resvr Inflow Apr-Sep 778 104 890 635 745
ELMM8N
Gallatin R nr Gateway Apr-Sep 260 57 347 206 455
GLGM8
Gallatin R nr Gateway Apr-Sep 260 57 347 206 455
GLGM8N
Gallatin R at Logan Apr-Sep 276 55 420 190 505
LOGM8
Gallatin R at Logan Apr-Sep 408 69 540 316 595
LOGM8N
Missouri R at Toston Apr-Sep 2206 88 2969 1842 2510
TOSM8N
Missouri R at Fort Benton Apr-Sep 3466 94 4637 2790 3690
FBNM8N
Missouri R nr Virgelle Apr-Sep 3975 93 5354 3188 4280
VRGM8N
Missouri R nr Landusky Apr-Sep 4240 94 5686 3384 4490
LDKM8N
Missouri R below Fort Peck Dam Apr-Sep 4391 93 5891 3479 4730
FPKM8N
Gibson Resvr Inflow Apr-Sep 468 117 640 387 400
AGSM8N
Marias R nr Shelby Apr-Sep 415 92 611 325 450
SHLM8N
Musselshell R at Harlowton Apr-Sep 64 61 112 37 104
HLWM8N
Yellowstone R at Yellowstone Lk Apr-Sep 592 74 747 476 795
YLOW4
Yellowstone R at Yellowstone Lk Apr-Sep 781 93 961 650 840
YLOW4N
Yellowstone R at Corwin Sprgs Apr-Sep 1478 79 1823 1239 1880
CORM8
Yellowstone R at Corwin Sprgs Apr-Sep 1784 90 2135 1487 1980
CORM8N
Yellowstone R at Livingston Apr-Sep 1809 85 2210 1523 2130
LIVM8
Yellowstone R at Livingston Apr-Sep 2176 94 2582 1805 2310
LIVM8N
Yellowstone R at Billings Apr-Sep 2766 74 3463 2162 3730
BILM8
Yellowstone R at Billings Apr-Sep 3784 89 4446 3097 4260
BILM8N
Yellowstone R at Miles City Apr-Sep 5643 78 7303 4462 7250
MILM8N
Yellowstone R at Sidney Apr-Sep 5799 77 7562 4585 7540
SIDM8N
Boulder R at Big Timber Apr-Sep 211 70 256 155 300
BTMM8
Boulder R at Big Timber Apr-Sep 252 78 297 195 325
BTMM8N
Stillwater R nr Absarokee Apr-Sep 334 66 420 267 505
SRAM8
Stillwater R nr Absarokee Apr-Sep 392 71 477 325 550
SRAM8N
Clks Fk Yellowstone R nr Belfry Apr-Sep 415 75 533 324 550
BFYM8
Clks Fk Yellowstone R nr Belfry Apr-Sep 486 81 602 398 600
BFYM8N
Bighorn R nr St. Xavier Apr-Sep 1660 65 2512 1160 2550
STXM8N
Little Bighorn R nr Hardin Apr-Sep 68 66 100 42 103
HRDM8N
Tongue R nr Dayton Apr-Sep 65 78 83 47 83
DAYW4N
Tongue R nr Decker Apr-Sep 146 68 216 98 215
DSLM8N
Tongue R Resvr Inflow Apr-Sep 148 69 223 99 215
DKRM8N
Powder R at Moorhead Apr-Sep 130 59 257 72 220
MHDM8N
Powder R nr Locate Apr-Sep 139 57 318 77 245
LOCM8N
Locations with an `N` suffix indicate natural flows excluding
stream augmentations.
KAF: Thousands of Acre-feet
%AVG: Current 50%/AVG
AVG: Average(50%) seasonal runoff voulme as simulated by the river
forecast model considering acontinuous simulation of the basin
response to historic climate data (observed precipitation and
temperatures) over the period of 1981-2010.
The 50%, 10% and 90% columns indicate the probability that the
actual volume will exceed the forecast for the valid time perion
for more information, please visit: www.weather.gov/mbrfc/water
