(Adds town name in paragraph 2; details of fire hazard in paragraphs 17-18)
By Keith Coffman
DENVER, March 27 (Reuters) - Forty-eight hours after a recent windstorm blew a wall of tumbleweeds into his community on the high plains of Colorado, Robert McClintock and his neighbors were still working to clear away heaps of the spiny plant.
"It was crazy. Some piles were more than 10 feet high," said McClintock, 38, as he and other residents in the town of Fountain, 15 miles (24 km) southeast of Colorado Springs, toiled to rake up and bag stacks of the thorny weed in the subdivision.
Prolonged drought, punctuated by bursts of high winds and untimely rain, has created an explosion of tumbleweeds on the rolling plains of southeastern Colorado, portions of New Mexico and the Texas panhandle this year, federal land managers say.
Tangled clusters of tumbleweeds clog drainage culverts, block rural roads, and plaster the walls of buildings, at times trapping residents in their homes.
While seen as a symbol of the American West, tumbleweeds are in fact a non-native weed - the Russian thistle - that was introduced into the United States in the late 19th century, according to the U.S. Department of Agriculture.
Ben Berlinger, a rangeland resources specialist with the U.S. Department of Agriculture's Natural Resources Conservation Service in La Junta, Colorado, said a "perfect storm" of conditions has allowed the weed to proliferate.
Berlinger said cattle ranchers have either sold off or moved their herds out of drought-parched grazing regions as a lack of moisture in recent years has dried up native forage, making more room for the hardy and largely drought-resistant tumbleweed.
With fewer livestock to keep the weed in check by grazing on its shoots, an unusual late summer rain last September caused the thistles to "take off," Berlinger said.
"They are opportunistic invaders that need just a little water to sprout," he said.
The weed can grow up to 3 feet (0.9 meter) high in summer, and when the plants dry out in winter, winds detach them from their roots and send them rolling across the landscape, spreading seeds as they go.
Rolling clusters of the tumbleweed have created havoc in the drought-stricken areas of the West.
In late January, an invasion of tumbleweeds rolled into Clovis, New Mexico, trapping Wilford Ransom, 80, and his wife, Mary, in their home.
"I looked out the window to see why it got so dark all of a sudden, and they were over 12-feet high, blocking my front and back doors," the retiree said. "We couldn't get out."
A neighbor eventually tunneled through the tangled mess to the Ransoms' garage, allowing the couple to escape.
In Crowley County, Colorado, tumbleweeds have blocked roads, making it difficult for emergency vehicles to reach certain areas, said Cathy Garcia, president of Action 22, an advocacy group made up of government and business leaders in the eastern part of the state.
The weeds also pose a fire hazard, Garcia said, because the dried-out plants are highly flammable and can ignite quickly if they come in contact with heated farm equipment.
Earlier this month, a prescribed burning operation to thin out vegetation at a wildlife refuge north of Denver quickly got out of control when scores of tumbleweeds were swept up in the flames.
The "fire whirl" was doused by firefighters already on the scene, but only after nearly 2 acres had been blackened, according to the U.S. Fish and Wildlife Service.
Irrigation canals clogged by tumbleweeds will need to be cleared before water can begin to flow to area farms and ranches this spring, Garcia added.
To combat the infestation, Garcia said her organization has formed a task force to come up with solutions that include lobbying federal and state governments for special funding.
"It has become a public safety issue," she said. (Editing by Steve Gorman, Gunna Dickson and Paul Simao)