 The Omak Stampede , which operates the Suicide Race , has been hosted at a local rodeo facility , the Stampede Arena — renovated in 2009 — since 1933 . The Omak Stampede occurs annually on the second weekend of August . During the event , the city has an estimated population of approximately 30 @,@ 000 people . As part of the Suicide Race , horses and riders run down Suicide Hill — a 62 @-@ degree slope that runs for 225 feet ( 69 m ) to the Okanogan River . Horses must pass a veterinarian examination to ensure they are physically healthy , and a swim test to ensure they can cross the river , to demonstrate their ability to run the race and navigate the river . Several animal rights groups , including Progressive Animal Welfare Society ( PAWS ) , In Defense of Animals and Humane Society of the United States ( HSUS ) , have expressed concerns about the horses ' welfare and have opposed the specific event . 
