The Californian Jorgenson won the Paris-Nice earlier in March and confirmed his burgeoning status in his first season with Dutch team Visma Lease-A-Bike.
Jorgenson broke away from an elite clique of six riders with a devastating turn of pace 6km away from the finish line after a 188km run with huge crowds.
"It's surreal," said Jorgenson, wiping tears from his eyes at the finish line.
Norway's Jonas Abrahamsen and the Swiss Stefan Kueng was third, 29 seconds off the pace.
More memorably a mass collision in the peloton caused by an uneven road surface felled up to a dozen unwitting riders, with Van Aert suffering major abrasions to his back as his yellow Visma team jersey was ripped almost entirely off.
"I was on Wout's wheel when it happened. It was a really ugly fall," said the winner.
"We were going so fast. My thoughts are with Wout and all the guys involved," said Jorgenson. "I have no news, all I know is he's in the hospital."
The accident occurred on a three-lane highway where there appeared to be one lane slightly higher than the neighbouring two.
Other high-profile riders hurt were Belgian Jasper Stuyven of Lidl-Trek and his Danish team-mate Mads Pedersen.
All four of those riders have won major classics and would have been contenders for the Tour of Flanders on Sunday and Paris-Roubaix the following Sunday, two major dates on the one-day racing calendar.
Van Aert was one of the favourites for Sunday's Tour of Flanders where up to 750,000 fans usually turn out for Belgium's biggest sports event.
Van Aert sobbed and rocked in agony as he was placed onto a stretcher and transferred to an ambulance.
Girmay's team Wanty confirmed the Eritrean "crashed hard during Dwars door Vlaanderen and is heading to hospital for checks".
