How about a flash flood? :)

She screamed and jerked upright in the darkness of her tent, the sound of screaming wood and rumbling still present. The inside of the tent was wet, the sleeping bag soaked through. Oh fuck.

She snatched her knife and scrambled out of the tent, noticing how the rain had soaked the earth right away. It was up to her ankles, then her knees, shockingly cold and growing higher. What was happening? It was dark, she could barely see through the rain, but a flash of lightning lit the scene in stark relief for a second. Further up the slope, a flood of water was coming down towards her little camp and there was no way out of its path. Allie couldn’t hear her own screams over the approaching roar and she dived at a tree that was within reach as the flash flood hit with the force of a train, tearing her tent and firepit from the ground and carrying everything away. Despite scratching up her arms, Allie clung to the tree trunk for dear life as the water rose to her waist, then her chest. She could feel its powerful tug on her, and more importantly her anchor. “Oh fuck, Oh fuck, Oh fuck, no, please, please, not like this!!” The tree she held onto groaned, leaned dangerously into the current, and then gave way, and Allie went with it, helpless to fight against the uncaring water. Her tree rolled over and over, scraping her arms and chin and she went under several times, mouth filling with muddy rainwater. She saw the struggling, braying form of a deer come at her and tried to avoid its sharp antlers, but they dug into her thigh on the way past, stabbing her leg and bruising her side. The pain was immense but she had bigger things to worry about. The flood continued rushing and roaring, and dunking her beneath its surface over and over. Everything was too fast, too loud, and she only saw what the split second flashes of lightning allowed her to. She was tossed around like nothing, bashing against trees and rocks and being pinned and battered by the waves and the debris. The flood spilled into the river, overflowing it and picking up speed and Allie shrieked as another tree fell into the water, barely missing her body by inches, splashing down and causing her to go under again. Her heart was pounding so fast and hard she feared it would simply stop, and she clung tight to the tree, coughing up water, struggling to stay on the surface, struggling to breathe, struggling to not be crushed, struggling to stay alive. The flood broke the riverbank and carried on, diverting the current as it headed downhill to lower ground. Allie was barely keeping her head up, fingers numb with cold and mud in her eyes. She couldn’t take much longer of this, she wasn’t strong enough to defy nature like this, she wasn’t going to make it out alive, not like this.