Rushing water gushes down through Seven Falls located in Bear Canyon. Mamta Popat/Arizona Daily Star

At about 2 p.m.on Saturday, Aug. 4, 2007, a wall of water cascaded over the top of a waterfall in Sabino Canyon.

Two people were killed. Fifty-four were stranded, including Aimee Snyder, a University of Arizona graduate student featured in a health story in today's Arizona Daily Star.

Snyder, then 24, was among those rescued by helicopter after the flash flood hit the Seven Falls area of the canyon.

Timothy Hahn, 25, and 19-year-old Angela Knoche died. Both had been on a hike with Snyder.

Knoche was swept away when the floodwater hit, and Hahn, a Staff Sgt. at Davis-Monthan Air Force Base, jumped in to help her and lost his life, too.

Snyder had been a lifeguard at the Davis-Monthan Air Force Base with Knoche.

The experience prompted Snyder to make bold life changes that had previously seemed too daunting. Always debt-free and frugal, she resigned a teaching job to go back to school for a master's degree, even though she'd have to take on student loans and live on very little money into her late 20s.

The tragedy also gave Snyder the courage to leave a marriage that had not been the right fit for some time. Life, she realized, was too precious. And too short.

As a memorial event for her friends, Snyder started a swim and run "aquathon" at Davis-Monthan  that is still going strong.

'It's a nice, healthy way to remember Angie and Tim and hold a long-lasting bond with all the people it affected in their memory.  Good for the heart," said Snyder, who remains close to Knoche's family. "I like to think of her as my guardian angel."