FLOOD POTENTIAL IN THE EASTERN GREAT BASIN

The following are generalized discussions of the flood potential due to snowmelt in the Eastern Great Basin drainage as of March 1, 1997. Discussions are segregated by state. It is important to understand that the potential for flooding may increase dramatically if snowmelt accelerates rapidly due to above normal temperatures or if significant rain events occur.

UTAH: At this time a high snowmelt flood potential exists for north and central sections of the Great Basin within Utah. As of March 1 a record or near record snowpack existed for many mountain locations. Forecast procedures indicate peak flows will exceed flood levels on the Logan River. Forecast procedures and flood levels do not exist for all rivers. Although specific peaks are unavailable, bankfull flows are expected on most northern Utah streams with over-bank flows possible on many of them. Of these streams the greatest snowmelt flood concerns at this time are on the Blacksmiths Fork, Little Bear River, American Fork River, Spanish Fork River, Jordan River, and their tributaries.

A moderate snowmelt flood potential exists in southern section of the Great Basin within Utah. March 1 snowpack, while not as significant as northern sections, is much above average. High flows are likely with some over-bank flows possible. At this time the area of greatest concern is the Beaver River and its tributaries.

The focus and seriousness of the flood threat may change significantly over the next several weeks due to the mountain snow accumulation and spring temperature scenarios.

IDAHO: The potential for snowmelt flooding in the Great Basin within Idaho is considered high at this time. Record or near record snowpack existed on March 1 throughout the Bear River Basin. Although flood levels and forecast procedures do not exist for specific sites, high flows, near bankfull are expected along the Bear and its tributaries with some over-bank flows possible