It smelled like gas, sulfur or something like that, and it woke her out of early morning sleep.

"I'm pretty sure I have a gas leak," a caller told Darren Wood, who was working the graveyard customer-service shift early Monday for Questar Gas.Questar and police agencies received call after call early Monday from people with similar worries about gas leaks in Salt Lake and Davis counties.

"Would you believe it's probably not a gas leak but the smell off the lake?" Wood told the caller.

Ah, summer. Time for recreation, family gatherings and the decomposition of little live things and foliage on the shores of the Great Salt Lake.

And what an olfactory sensation that decomposition can bring.

Water in the huge lake reached its high point in early July but has been dropping since then, and when it does, living things underwater surface, die and decay, said Larry Anderson, director of water resources for Utah's Department of Natural Resources.

"It's generally a pretty distinct odor," he said. "As the lake continues to go down, that smell hangs around until this fall when things cool off and the lake starts moving back up."

About 40 people like the woman caller telephoned Questar as they woke up and noticed the odor, said Steve Chapman, a Questar spokesman.

The substance the gas company adds to the naturally odorless gas, Mercaptan, really doesn't smell like the lake, Chapman said. "People assume since it's a smell they can't identify that its probably gas."

About once a year, the wind blows in a way that makes people believe their furnaces or water heaters are emitting toxic gas, Chapman said.

People who suspect gas leaks during a time when the lake is smelly can walk outside to determine if the odor is coming from inside or outside of their home. The smell is typically much stronger if it's coming off the Great Salt Lake.

A group of thunderstorms formed over the Great Salt Lake between 9 and 10 p.m. Sunday and stirred up enough commotion to blow the increasingly noxious smell of the lake into Davis and Salt Lake counties, said Bill Alder, a spokesman for the National Weather Service office at the Salt Lake Airport.

"The smell's there, it's just a matter of bringing it into the populous," Alder said.

Alder said the combination of thunderstorms and wind was "kind of a goofy thing to happen," and he doesn't expect like circumstances in the next few days.