(CNN) -- A suspected tornado touched down in south-central Texas on Monday, the National Weather Service said, as a slow-moving line of storms brought high winds, heavy rains and large hail as it swept eastward.
The Medina County, Texas, Sheriff's Office "received over 300 calls indicating there is damage or injuries" due to the storm, said a woman from the sheriff's office who identified herself only as Heather.
This came after one twister landed around 8 p.m. Monday near Natalia, a town of about 1,400 residents that is in the county.
"It struck us pretty hard," she said from the county, which is about 30 miles west of San Antonio. "At this point, we have unknown (amount) of injuries, but we have a lot of damage."
Charlie's Ice House, a bar in Devine, was in shambles after potent winds barreled through, ripping off its roof.
"It happened so fast and everyone was getting away from the doors ... and then it was over," said co-owner Marilyn Banks, adding that none of the 20 to 25 people inside suffered much more than a few scratches.
Authorities, though, are "in rescue mode" searching for a motorcycle rider who is unaccounted for since the system came through, said Lawrence Trevino, San Antonio's emergency manager who is assisting neighboring counties in the response.
He said that some injuries have been reported, but there are no known deaths after the strong winds damaged about six homes.
Joanne Ortiz said she saw what appeared to be three funnel clouds from her home in Devine. While tornadoes are not new to the area, she said the fact they came in rapid succession was alarming.
"At first we were fascinated by it. But once we saw two of them, we thought, where do we go?" said Ortiz, who lives in a one-story manufactured home on a 3-acre lot.
In Bexar County, which includes San Antonio, Fire Marshall's Office spokeswoman Laura Jesse said there "are reports of damage to one home in southwest Bexar County" but otherwise the impact appears to be limited.
"This is a rural area, so it's not that populated," Jesse said.
Parts of north, south and central Texas, including the Dallas-Fort Worth area, were under a tornado watch, the weather service said.
The tornado is related to a weather system that's also triggered flash flood watches and warnings for sections of Arkansas, Oklahoma, Texas and Louisiana. The threat of heavy rain will continue across the area into Tuesday.
Meanwhile, much of the eastern two-thirds of the country continued to have unseasonably warm temperatures, a day before spring officially starts.
Parts of Arizona remained buried under snow Monday as a surprising late-winter onslaught paralyzed travel and closed schools.
The weather agency issued a winter storm warning for the mountains of central and eastern Arizona through early Monday. Another winter storm warning was issued Monday afternoon for parts of southeast Arizona.
The city of Flagstaff was still digging out of 10 to 14 inches of snow from the weekend, which prompted school closings in the city. The city of Prescott received 8 to 12 inches.
Brandon Neuman of Flagstaff produced a time-lapse video of about a foot of snow falling on his backyard deck in seven hours.
"The other day it was 65 degrees, next day it is snowing, so it's been crazy," Neuman said. "It killed a lot of people's travel plans because the highways are a mess."
But in eastern parts of the country, balmy conditions prevailed, with temperatures well above average from Texas and the Midwest all the way to the East Coast.
CNN's Jessica Jordan, Greg Botelho, Nick Valencia, Sean Morris, Leslie Tripp, Pedram Javaheri, Karol Brinkley, Maggie Schneider and Ashley Hayes contributed to this report.