Weather Awareness
Weather is the other major safety variable when you're alone on the water. The three threats to take seriously: lightning, flash floods, and hypothermia.
Lightning
You are standing in water, holding a nine-foot graphite rod over your head. Lightning and fly fishing do not mix. If you hear thunder, see darkening skies, or notice that the hair on your arms is standing up, get off the water immediately. Don't wait for rain. Lightning can strike miles ahead of visible storm clouds. Move to your vehicle or a substantial building — not under a lone tree.
Flash Floods
Flash floods are a real risk on many trout streams, especially in mountainous terrain or canyon drainages. A storm that's miles upstream can send a wall of rising water down a drainage while you're standing in perfectly clear skies. Watch for sudden changes in water color (turning muddy), rising water levels, and increasing debris in the current. If the water starts rising, get to high ground. Don't try to wade back to your original bank — go to the nearest bank.
Hypothermia
You don't have to fall in to get hypothermic. Cold rain, wind, and wet wading on a cool day can lower your core temperature gradually enough that you don't realize it's happening until your coordination starts failing. Dress in layers, bring a rain jacket even on nice days, and carry a spare dry base layer in your pack if you're fishing in cool conditions. The early signs — shivering, clumsiness, confusion — are your signal to get off the water, get dry, and warm up.
Wildlife Considerations
The vast majority of wildlife encounters while fly fishing are harmless and wonderful. You'll see herons, kingfishers, otters, deer, and if you're lucky, the occasional eagle or osprey pulling a fish from the water right in front of you. But two categories deserve awareness, not fear.
Bears
In bear country — and much of the best fly fishing in the West and Northeast overlaps with bear habitat — take basic precautions. Make noise as you move along the stream so you don't surprise a bear at close range. Carry bear spray in an accessible holster on your chest or belt, not buried in your pack. Be especially alert during salmon runs, near berry patches, and in areas with limited visibility. If you encounter a bear, stay calm, speak in a low firm voice, make yourself look large, and back away slowly. Do not run.
Snakes
Watch where you step and where you put your hands, particularly along rocky banks, deadfall, and tall grass near the water's edge. Most venomous snakes in North America — copperheads, cottonmouths, rattlesnakes — are not aggressive and will avoid you if they know you're coming. Wear boots (not sandals), watch the ground ahead of you, and give any snake you see plenty of space. In decades of fishing, most anglers can count their close snake encounters on one hand.