DENVER (AP) -- More spring thunderstorms delivered hail and triggered tornado sirens in Colorado on Thursday as hail storms, small tornados and strong winds hit states in the West and Northeast.
In Colorado, heavy hail briefly pounded downtown Denver, and more hail was reported in Red Feather Lakes northwest of Fort Collins. Campers in the campground of Bellaire near Red Feather Lakes were evacuated after hundreds of trees were knocked down, blocking roads into the campground as the Memorial Day holiday weekend got underway. There were no reports of injuries.
The National Weather Service has not confirmed if a tornado touched down in the area. The area was under a tornado warning earlier in the day.
Fans watching the Colorado Rockies play the San Francisco Giants at Coors Field were told to seek safety in a lower concourse as tornado sirens wailed. The tornado warning soon expired. Several incoming flights to Denver International Airport were delayed to let the storm pass, airport spokesman Heath Montgomery said.
In New Mexico, severe weather and large hail caused multiple car wrecks in the northern part of the state Thursday. Elsewhere in the West, a small tornado in a rural area of eastern Idaho on Wednesday caused no damage or injuries, authorities said.
In the eastern United States, hail and strong winds caused damage in Virginia, New York state, Delaware and Pennsylvania.
A jetliner that flew through a hailstorm on its descent into Philadelphia 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.
In Delaware, two people were injured when high winds damaged about a dozen homes in the Kent County community of Marydel, emergency officials said Thursday.
No significant damage was reported from Colorado's twisters, and the latest round of storms wasn't expected to be as extreme or as widespread as that seen Wednesday.
Three of Wednesday's tornadoes touched down in and around Aurora. Others hit north and east of Denver.
Frontier Airlines canceled some flights after six of its planes were damaged by hail Wednesday. A microburst was blamed for ripping a section of metal sheeting off the roof of Castle Rock's town pool.
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 were investigating whether a software error was to blame.
Lower-level winds weren't forecast to be as strong Thursday, which meant any tornadoes would likely be short-lived, National Weather Service meteorologist Kari Bowen said.
The chance of afternoon thunderstorms along Colorado's Front Range will continue through Memorial Day weekend. Besides the risk of tornadoes, heavy rain could cause flooding if storm cells hit areas burned by recent wildfires.