A huge toxic algal bloom in Utah has closed one of the largest freshwater lakes west of the Mississippi River, sickening more than 100 people and leaving farmers scrambling for clean water during some of the hottest days of the year.

The bacteria commonly known as blue-green algae has spread rapidly to cover almost all of 150-square-mile Utah Lake, turning the water a bright, anti-freeze green and leaving scummy foam along the shore.

Utah Poison Control has fielded hundreds of cases related to the bloom, including some 130 involving people who have reported vomiting, diarrhea, headache and rashes.

It's also a major blow for growers and businesses that rely on the lake.

For now, authorities are waiting for the bloom to run its course and clear up, hopefully aided by a drop in temperatures or a storm that could stir up the water and reduce water stagnation.