BEMIDJI, Minn.  Ziggy Zerott arrived at his modest downtown clothing store, Cool Threads, in this small northern Minnesota city on Thursday morning to find something he had never seen in his 27 years of business: a line. Fifteen to 20 people, he said, were waiting for him to open.

Four days earlier the men’s hockey team from little Bemidji (Be-MIDGE-ee) State University, Zerott’s alma mater, had advanced to the Frozen Four, the semifinals of the N.C.A.A. hockey tournament, for the first time. Zerott stocks Bemidji State apparel, and once Beavers fans heard Frozen Four T-shirts had come in, a run was on. Unwilling to let customers stand in the cold, Zerott opened his store with the imitation log cabin front a half-hour early, at 9:30 a.m.

“By 10:15 we were wiped out,” Zerott said. The day’s receipts, he said, exceeded his previous best day by 50 percent. “And Friday was a little bit better,” he said. So on Saturday, when Cool Threads is normally closed, Zerott and an employee manned the register while customers perused racks of green B.S.U. gear.

Image Senior forward Tyler Scofield scored nine of his 22 goals on Bemidji States strong power play, which ranks sixth in Division I. Credit... Bemidji State University

“We can’t even keep up with our regular Bemidji State stuff,” he said. “We didn’t expect this. I was in Grand Rapids for the regional. I didn’t think we’d beat Notre Dame.”