March 21, 2023 |
Photo – Cloud Seeding Plane – Courtesy North Dakota State Government
Cloud-seeding operations over the Sierra Madre Mountains in Carbon County were suspended last week because of concerns over the amount of snowpack in the Little Snake River drainages this late in the season.
The Wyoming Water Development Office announced the shutdown yesterday in a news release. The WWDO said the snow-water-equivalent levels at SNOTEL sites, monitored by the National Resources Conservation Services, “exceeded operational criteria forcing the immediate suspension of cloud seeding operations.”
The cloud seeding season began on November 8 in the Sierra Madres, the Snowy Range, and the Wind River Mountains. Operations will continue in the Snowies and the Wind Rivers, unless snow-water equivalent values exceed suspension criteria prior to April 22.
The threshold for suspension is 85% of median, April 1 value, for each of the targeted mountains and increases daily to 140% of the April 1 value by April 1. Barry Lawrence, Deputy Director of the WWDO, said the Sierra Madres hit a point of no return last week.
On March 20, 2023, the snow-water equivalent, for the nine SNOTEL sites monitoring the Little Snake River, were reporting an SWE of 156%.
The 20 sites that monitor the Upper North Platte River reported an SWE of 128% of median.
The Wind River has 11 SNOTEL sites and reported an SWE of 115% of median.
Cloud-seeding in the Snowy Range and Sierra Madres ran as an experimental, ground-based research program, from 2005 to 2014. The pilot program collected enough data to convince the legislature to fund a fully operational program. The WWDO now uses airplanes to inject storm clouds with silver iodide particles to promote the formation of snow in storm clouds. Two ground-based generators in the Sierra Madres augment the process, which costs the state around $1 million a year.
The goal is to increase mountain snowpack incrementally to improve stream flows in the North Platte and Little Snake River basins.
