LANDER -- A massive, slow-moving storm that slammed the Northern Rockies in the past few days not only caused twisters, hail and high winds, but it dumped record-breaking amounts of precipitation in central Wyoming.

The Lander area has now recorded its wettest May ever, as of Tuesday, said meteorologist Don Day with DayWeather, a private weather center in Cheyenne.

Another spot, six miles northeast of Glendo -- which averages about 13 inches of precipitation annually -- was doused with more than 8 inches of rain in just five days, Day said.

And the counties of Platte, Converse, Natrona, Fremont, Hot Springs, Johnson, Sheridan and Campbell all received, on average, about 2 to 5 inches of moisture since Thursday, he said.

"What a difference a week makes," Day said. "The whole state has been beneficially and adversely affected at the same time, going back to last Thursday."

With 6.08 inches of rain so far this month, Lander has already surpassed its previous record total of 6.03 inches that fell in 1957.

Of Lander's record-breaking precipitation, nearly 5 inches fell between Thursday and Tuesday.

May is usually the wettest month of the year for most of Wyoming, and Lander receives an average of 2.4 inches of precipitation during that month.

"What's amazing about this is that Lander, just a couple weeks ago, was on track for one of its driest Mays ever, if not its driest," Day said. "It went from the driest to the wettest in five days."

The recent storm system -- when it was at its largest on Thursday and Friday -- ranged from parts of California to Colorado, and from Alberta, Canada, down to the Mexico border, Day said.

On its most turbulent day, Thursday, the storm produced a deadly tornado just east of Fort Collins, Colo., dropped 6 inches of snow on Thermopolis, created funnel clouds in Laramie and Albany counties, and caused flooding, hail and high winds in several places throughout the Cowboy State.

In addition to a tornado and high winds Thursday, Laramie also received almost 3 inches of moisture over the weekend.

Pieces of the storm were still hanging over Wyoming Tuesday, Day said.

Temperatures should warm up throughout the state in the coming days, he said, and because there is still a good deal of snowpack in the mountains, there could be a danger of flash floods in the coming weeks.

Wyoming residents can also expect regular afternoon and evening thunderstorms in much of the state for the rest of May and into June.

"While I don't see episodes as cold as this last one, the forecast certainly does favor more rain," Day said. "This storm really soaked the West, and there's quite a bit of soil moisture now, which tends to get recycled a little bit."

When an entire region gets a good soaking, as Wyoming did this past weekend, it can lead to a wetter weather cycle, Day said.

"I'm not saying the drought is over, but this certainly helps," he said.

Riverton saw record single-day rainfall totals in two out of the storm's five days, said Jim Fahey, hydrologist with the National Weather Service there.

Although there has been some flooding in Buffalo and Kaycee, the reported damage was minimal as of Tuesday, Fahey said.

Dave Scheibe, with the National Weather Service in Riverton, said the recent storm produced its relatively huge amounts of precipitation after a cold front moved into the Cowboy State and then stalled over south-central Wyoming. This, coupled with damp, upslope winds, caused the air to cool rapidly and drop much of its moisture.

Amy Johnston, who grows hay and food crops and raises cattle outside of Wheatland, said the recent rains might not have lifted the region out of drought, but it's still been a boon for her operation.

Some areas west of Wheatland got about 7 inches of rain recently, and her place southeast of town received about 4 to 4.5 inches, Johnston said.

"It's wonderful," she said. "It helps immensely. We're able to irrigate probably 85 percent of our hay meadows and our crops, but this just helps everything. It helps save water, and it helps the rangeland for the cattle. And there's just something better about rain."

Johnston farms hay, sugar beets and beans -- and it all grows healthier with rainwater, as opposed to irrigation water, she said.

"It's what my father always used to say, and I don't think I believed him," Johnston said. "But it's true. Rainwater just does something different."

Heavy spring and early summer precipitation can lead to increased fire danger in the late summer, said Greg Bevenger, a hydrologist with Shoshone National Forest, but it's still too early to tell if that scenario will play out this year.

"When we get these spring rains like this, it helps all of the various kinds of grasses grow. And once they start to dry out at the end of August and September, they can help carry those fires across the landscape," Bevenger said.

However, parts of the state commonly get moisture at the end of July and early August, which can come up from the Gulf of Mexico, and which can douse the grasses enough to prevent widespread burning, he said.

Regardless of the potential fire danger, the moisture is more than welcome after several years of drought, Bevenger said.

"These recent storms have increased the soil moisture higher than we've seen in many, many years," he said. "It should allow for a lot of forage growth for livestock and wildlife. It may influence the fire season, but it may not. It's really too early to tell."

Environment reporter Chris Merrill can be reached at chris.merrill@trib.com or at (307) 267-6722.

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