Disaster aid will be slow to come for South Dakota ranchers who lost as many as 60,000 head of cattle during an historic blizzard over the weekend, industry officials said on Tuesday.

Cattle died of hypothermia or suffocated under snowdrifts after a “perfect storm” brought rain, then record snowfall and strong winds to the portion of the state west of the Missouri River, said Silvia Christen, executive director of the South Dakota Stockgrowers Association.