Physical conditioning, the type of trip, weather, and tides and currents. Water is usually available from many streams that run from mountainsides. In planning your trip the vessel regulation map shows areas where the Park Service has restricted boats and visitors due to wildlife. Hypothermia means lowered body temperature. It can happen not only from cold water immersion but from cooling due to exposure to rain and wind.
Proper clothing is essential.
If you are planning an open water crossing it is recommended that you wear a dry suit. Avoid capsizing if you are not prepared for exposure by wearing a dry suit. If you capsize not wearing a dry suit re-enter your kayak immediately to avoid hypothermia. Be aware of changing water conditions. Currents can be strong and swift.