The hail storm that swept through central Ohio on April 5 was followed by weeks of work by home repair contractors.

The hail storm that swept through central Ohio on April 5 was followed by weeks of work by home repair contractors.

Hail stones as large as 1.25 inches in diameter were reported in the Grove City area.

Grove City homes, particularly those on the west side, were left with damaged roofs and siding.

Between the storm and the end of May, 217 housing contractors registered with the city and construction permits soared.

In May, 569 residential building permits were issued, according to the city's building and zoning division report. Of that number, 400 were for roofing or siding replacement. The May numbers were slightly higher than those in April.

"Numbers for both April and May exceeded by more than 200 the next-highest monthly totals for the last three and a half years," officials wrote in the report.

According to the Ohio Insurance Institute, the April 5 storm was not catastrophic because damage didn't exceed $25 million.

"Our initial estimates did not rise to a catastrophe loss," insurance institute spokeswoman Mary Bonelli said. Investigators are likely to revisit the storm losses six to 12 months afterward to determine if their initial impressions were correct.

But on the face of it, Bonelli said, 217 new contractors in Grove City "is an alarming number.

"I'm not saying they are all out-of-state storm-chasers but they could do the work and then leave. Then if a problem develops later, there's no one for the homeowner to call."

Bonelli said the incidence of storm damage claims in Ohio has risen dramatically. Questionable claims in Ohio also have risen in the past four to five years.

Disreputable contractors can falsify damage assessments and convince unwitting homeowners to file claims. Some have even manufactured the damage where none existed, using ball peen hammers or twisting dimes to damage shingles or siding, she said. Others offer local businesses a percentage of their sales if they allow the out-of-towners to use their names to solicit business.

Questionable claims are getting coordinated attention from the Ohio Insurance Institute, the Ohio Department of Insurance, the National Insurance Crime Bureau and the Better Business Bureau.

A National Insurance Crime Bureau study found that the number of damage claims rose 61 percent to more than 413,000 nationally from 2006 through 2009. The number of questionable claims jumped 136 percent, to 711.

Ohio ranked seventh in both claims and questionable claims, according to the study.

Meanwhile, the National Weather Service has changed its criteria for severe thunderstorm warnings after conducting research of its own.

The minimum size hail for weather service warnings was increased from 3/4 inch (penny-size) to 1 inch (quarter-size) nationwide on Jan. 5. Forecast wind gusts of 58 mph for storm warnings was left unchanged.

"This change is based on research indicating significant damage does not occur until hail size reaches 1 inch (quarter-size) in diameter," a National Weather Service press release said.

The change also was in response to requests by emergency management officials and the media.

"Particularly in areas of the Central U.S., the frequency of severe thunderstorm warnings issued for penny-size and nickel size hail might have desensitized the public to take protective action during a severe thunderstorm warning," the weather service said.

After testing the larger hail criteria for warnings in parts of Kansas last year, "the emergency management community in those areas agreed that warnings carry more weight, and (weather) spotters now concentrate on the more significant events."