Sandra Rose hikes frequently in East Bay Regional Parks and is no stranger to rattlesnakes. Last month, she saw three in one week.  “We all heard the hiss as the snake went up the hill.” Rose said, referring to a hike in Sibley Volcanic Regional Preserve in Oakland. Rose says she expects to see snakes in the park. “They won’t bother you if you don’t bother them,” she said. “I’m not scared of them, I think they’re fascinating.”  Last month,…