A ball of garter snakes

What is a snake ball?

Indiana Jones’s worst nightmare occurs every spring throughout North America, when garter snakes emerge from their winter hibernation to participate in romantic entanglement. Places to tread softly: Great Smoky Mountains National Park, TN/NC; Glacier National Park, MT; Yosemite National Park, CA; basically everywhere.
No metaphor: A snake ball is literally a ball of breeding snakes (typically garters). Between 10 and 100 male snakes may writhe about one female (or, sometimes, a man posing as a female) in an effort to mate, making a wriggling, rubbing bunch of horny reptiles. After anywhere between one hour and per day, just 1 man receives the chance to breed. 
Nothing quite says”warm weather” like wild snake orgies. Here’s everything you never wanted to know about trailside tangles of slithering serpents.

Where could they be viewed?