Jumping is out of the question. If the banks are rocky, then there's a chance that the riverbed is also rocky and might kill her instantly and she doesn't want that. Not that she knows any kind of attempt is as risky.

She'll leave her lantern and the torch on the banks and try to sit on the rocks first to look at the debris more closely. A few minutes later, she'll attempt to slowly descend from the rocks—or as slowly as she can, given the state of the boulders. If she feels like she's falling, she'll try to scramble back up if possible.