More storms rolling into Colorado

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A cloud drifts away leaving behind fresh hail, east of Denver, Wednesday, May 21, 2014. Denver International Airport was cleared to resume operations after severe thunderstorms and a tornado warning grounded flights. (AP Photo/Brennan Linsley)

DENVER (AP) — More spring thunderstorms began rolling into Colorado on Thursday as hail storms, small tornados and strong winds hit states in the West and Northeast.

In Colorado, heavy hail was reported in Red Feather Lakes northwest of Fort Collins, and more hail is falling in Denver. Fans watching the Colorado Rockies play the San Francisco Giants at Coors Field were told to seek safety in a lower concourse at the baseball stadium because of a tornado warning. That warning later expired.

Elsewhere in the West, a small tornado in a rural area of eastern Idaho on Wednesday caused no damage or injuries, authorities said. In New Mexico, severe weather and large hail caused multiple car wrecks in the northern part of the state Thursday.

In the eastern United States, hail and strong winds caused damage in Virginia, New York state and Pennsylvania. A jetliner that flew through a hailstorm on its descent into Philadelphia has landed with a cracked windshield. US Airways says only one layer of the multilayered windshield was cracked and Flight 768 en route from Orlando, Florida, landed safely. No one was injured.

No significant damage was reported from Colorado's twisters, and the latest round of storms isn't expected to be as extreme or as widespread as that seen Wednesday.

Three of the tornadoes touched down in and around Aurora, while the others hit north and east of Denver, including one about 13 miles from Denver International Airport.

There weren't any tornadoes in Lafayette, north of Boulder, but some residents probably got a scare when tornado sirens mistakenly sounded around 3 a.m. Thursday. Engineers are investigating whether a software error was to blame.

Hail covered roads and grass in some parts of the Denver and Colorado Springs areas, with snow plows called out to clear runways and the access road to the airport. Golf ball-sized hail piled up 4 inches near Strasburg on the plains 40 miles east of Denver, the National Weather Service said.

The storms temporarily grounded flights at the airport and forced 40 flights to be diverted Wednesday. Frontier Airlines canceled some flights after six of its planes were damaged by hail. It is waiving change fees for passengers who need to rebook their flights through Thursday.

A microburst is blamed for ripping a section of metal sheeting off the roof of Castle Rock's town pool.

Lower-level winds aren't forecast to be as strong Thursday, which means any tornadoes that form will likely be more short-lived, National Weather Service meteorologist Kari Bowen said.

The chance for afternoon thunderstorms to develop will continue through Memorial Day weekend. Besides the risk of tornadoes, heavy rain could also cause flooding if the cells hit some of the areas burned by recent wildfires.