LANCASTER, N.H. » Safety officials in New Hampshire worked through the night investigating the collapse of a circus tent during a severe storm that killed two spectators and injured at least 22 other people.

Authorities were looking at how the tent was put up at the Lancaster Fairgrounds, about 90 miles north of the capital of Concord. They also were talking to survivors and witnesses.

Fire Marshal William Degnan said it was the first time his agency had investigated a tent collapse.

The storm, packing 60 mile-an-hour gusts and hail, blew through around 5:30 p.m. Monday, just as the first of two scheduled shows was beginning.

Degnan said about 100 people were inside the tent at the time, and a man and a girl died. Their names were not released. The injured were taken to four regional hospitals. Their conditions were not immediately known.

The circus operator, Sarasota, Fla.-based Walker International Events, did not return a call seeking comment late Monday. The circus was scheduled to head to Bradford, Vermont, for shows on Tuesday and Wednesday.

The National Weather Service had issued a severe thunderstorm watch for the area during the time of the collapse but Degnan couldn’t immediately say if the spectators were aware of the storm’s strength.

The collapse comes a day after one man died and more than a dozen were injured when a tent where people had sought shelter during a brief storm blew off its moorings and fell on some of the crowd at a festival in a Chicago suburb. The annual celebration known as the Prairie Fest had attracted about 5,000 people when the tent collapsed.

The popular Lollapalooza music festival in Chicago’s Grant Park briefly shut down Sunday afternoon due to the weather, then resumed less than an hour later. Organizers ended the final day of the festival 30 minutes early Sunday night when another storm hit the area.