Sakakawea outlook below normal
This year is setting up to be one in which little gain is in store for Lake Sakakawea in terms of elevation. Even the recent storm that brought a substantial amount of snow to much of North Dakota might not prove to be of much help.
In the March 1 forecast of annual runoff issued by the U.S. Army Corps of Engineers, the projected amount of water expected to enter the Missouri River Basin in 2013 increased only slightly from 19.5 million acre feet in February to 20.0 maf as of March 1. The historic average for the system is 24.8 maf.
Of notable interest is the consistency of winter snowfall over the two major impact areas that influence how much water will enter the Missouri River system and, eventually, Lake Sakakawea. Snowpack water content is tracked throughout the winter “above Fort Peck” in Montana and “Fort Peck to Garrison” in North Dakota.
The total above Fort Peck is primarily what is known as the Upper Missouri River drainage, which originates on the east side of the Rocky Mountains in Montana. The Fort Peck to Garrison outlook includes the Yellowstone River and the plains snowpack. The Yellowstone joins the Missouri above Lake Sakakawea. Snowfall and water content in those two forecast areas has remained nearly constant this winter.
On Jan. 31 the snowpack water content above Fort Peck was listed at 92 percent of average. From Fort Peck to Garrison it was 84 percent. Feb. 26 surveys placed the former at 93 percent of average and the latter at 86 percent. Those percentages on March 5 were listed at 94 and 86, meaning a continuation of a trend that began in the early stages of the winter season.
Unless there is a significant change in snowfall totals in the weeks ahead, or heavy rainfall, it is increasingly evident that earlier projections for a minimal rise in Lake Sakakawea this summer will hold true. It should be noted that March, even April, can produce major snowfalls. The average peak date for mountain snowfall in Montana is April 15.
Although the most recent elevation projections for Lake Sakakawea were not available at press time, it is not expected that forecasted water levels would change much from the Feb. 1 outlook. The February forecast called for a peak elevation of 1,831.9 feet for Lake Sakakawea in July. The long-term average for July is 1,840.5 feet. Lake Sakakawea stood at 1,827.3 feet Tuesday.