SNOHOMISH COUNTY, Wash. — Colder fall weather won't stop many hikers from hitting the trails in the Pacific Northwest. That's why a wilderness survival expert said hikers should know what they could face this fall.

Over the weekend search and rescue crews were pretty busy along the Pacific Crest Trail. It was snowing heavily when a 41-year-old hiker fell into a creek. He was having medical issues and had to be rescued. A 76-year-old man also needed to be rescued after falling and hitting his head along the trail.

A wilderness survival expert in Snohomish County said hikers need to be prepared and bring the right tools with them.

"I think it's the time of year where you pack extra layers. An easy way to do it is to get one of those raincoats that packs down into a small bag," explained Alderleaf Wilderness College Program Director Jason Knight. "Have a first aid kit, ways to make fire, an emergency blanket, and water purification means."

Also see | 10 essentials every hiker should have to stay safe on trails

Hikers should have a plan and let someone know where they are going before leaving for a hike and when they plan to return.  

Knight said lost or injured hikers can reach dangerous levels of hypothermia after just three hours of being in the cold. Humans can go three days without water and three weeks without food.

Hikers need to make sure they always have the 10 essentials with them: a firestarter, a map and compass (if you're not carrying a GPS), tools such as a knife and repair gear, a headlamp, a first-aid kit, sun protection, shelter, food, water and rain gear and insulation.

Also see | Five hikes for seeing fall colors in Western Washington