Swimming in the San Francisco Bay is likely a frigid experience.
Three hundred athletes who dove into the bay Monday morning, however, were in for an even chillier challenge than usual.
Participants in the fourth annual Orca Alcatraz Challenge Aquathlon & Swim braced extremely strong currents and temperatures in the 50s during their one-and-a-half mile swim from Alcatraz to the East Beach of Crissy Field beginning at 8 a.m. Upon emerging from the freezing water, several participants continued their journey with a seven-mile run through the city.
The event, sanctioned by USA Triathlon, recommended that swimmers wear wetsuits and hoods to help them withstand the harsh temperatures and currents.
The current on Monday was strong enough to carry a non-swimming person three miles west in just one hour.
Parker Smith, a 17-year-old from Seaside, crossed the Aquathlon finish line first in the men's category, clocking his arrival at 1:21:35. The first female to finish, Patricia Lai, 31, of San Francisco, came in at 1:32:04.
