WMOD00270 (2) - Laserfiche WebLink

Home Browse Search

NA we's Suspension Procedures NA WC's suspension policy concerning Traveler's Advisories, Heavy Snow Warnings and Winter Storm Warnings is based upon the intent of its weather modification operations. In that regard, winter orographic seeding is conducted for and limited to increases in snowpack in the high runoff yield areas (i.e., high elevations). Therefore, such operations would not adversely affect driving conditions in the valleys. Additionally, the amount of snowfall increases from seeding alone, in mountainous terrain, is not envisioned to produce heavy snowfall (that is, the heavy snowfall conditions would be present without seeding). Concerning Winter Storm Warnings the same reasoning for T A's applies, in addition to the fact that weather modification operations do not affect the parameters (wind and temperature) included in the NWS's criteria for issuing the warning. It is therefore NA WC's policy that winter orographic seeding will not be suspended solely upon the issuance of Traveler Advisories, Heavy Snow Warnings, or Winter Storm Warnings. Concerning Flash Flood Warnings, NA WC will suspend seeding operations upon individual convective systems or areas in which warnings are issued that impact Gunnison County. This action will be taken to avoid any appearance of contributing to damaging weather situations. On some programs, limits are set on the percent of normal levels of either precipitation or snow water content at Natural Resources Conservation Service (NRCS) mountain SNOTEL or snow course sites, within or adjacent to the intended target area of the project. Data are available from SNOTEL sites on a daily basis. Ifthese limits are exceeded, then seeding is suspended until the percent of normal falls under the limit or the project is terminated for the season. This procedure is designed to curtail seeding in above normal snowpack years that may produce high spring and/or summer streamflow. Such a procedure was used in the conduct of the earlier programs in this area. It is proposed that the NRCS SNOTEL sites listed in Table 2. Seeding suspensions will be based upon averages of snow water content from the SNOTEL sites provided in Table 2. Seeding will be suspended whenever these averages exceed the following percentages: · 175 % of average on December 1 st · 175 % of average on January 1st · 160% of average on February 1st · 150% of average on March 1 st . 140% of average on Aprills1 10