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How to Swim Safely in Cold Water Lakes

Washington state is full of beautiful mountain lakes — and many of them are very cold. Here's what you need to know to swim safely — and protect the fragile lake environment.

By Julie Popper

How do you feel about taking a plunge in 50-degree water? Our region’s alpine lakes are stunningly beautiful — clear, clean and sparkling. It’s hard to look at them without thinking about jumping in, but dipping a hand into the lake quickly indicates the water is really, really cold. That shouldn’t stop most people from trying a refreshing swim. You’ll just want to keep safety and some basic tips in mind.

Recent studies have suggested that cold water swimming can be good for your mental health. A growing group of “wild swimming” enthusiasts is taking up the sport and testifying to its benefits. With a little preparation, if you’re a confident swimmer, you can join them.

A swimmer swims toward an island in a clear mountain lake.
Remember that cold water can affect your swimming form. Be careful not to swim too far. Photo courtesy Julie Popper.

Keep it safe

Particularly if you’re a beginning cold water swimmer, have someone with you. The cold water can increase the likelihood of heart problems or cramps that even experienced pool swimmers aren’t expecting. If you’re not a confident swimmer, it’s better to start in warmer and predictably shallow waters.

Distances over water look shorter than they are so be cautious before making a distant object your goal. Also, water depth can be extremely hard to estimate visually — worth noting if you’re a swimmer who likes to just jump in. Finally, if you’re used to a 45-60 minute swim workout, remember that might be too long to be in cold water. Pay attention to signs your body is giving you (shivering, tingling, etc.) and get out before you get too cold.

Get in slowly, get out quickly

Our bodies adjust best to the cold water if you slowly wade in. A quick entry into especially cold water can be a shock that leaves you gasping and could lead to drowning. A slow entry is key. Once you’re up to your shoulders, dunk in all the way a few times and you’re good to go. As you finish swimming, step out quickly and wrap yourself in a towel, and change into dry clothing as soon as you can.

Before jumping in, think about what your experience will be like getting out. What are the indicators that your body is getting cold and you need to get out? Many people lose swimming form or efficiency as they get cold, could have tingling fingers or toes, or begin shivering. Don’t wait until it’s too late. Also consider your exit path. Is there a clear path out or will you have to climb? (Can you do that climb if you’re shivering or your fingers get numb?) Have your towel ready and try to have some other warm stuff waiting for when you’re back.

Julie swimming. A woman floats in blue lake water, wearing goggles and a swim cap.
Before you get in to swim, it's important to have a plan for how you'll get out safely and to get out before you get too cold. Photo courtesy Julie Popper.

Keep the water clean, STEP LIGHTLY ON SHORE

Sunscreen, bug spray, lotions, makeup, and hair products can all add foreign pollutants to these lovely waters. If you know you’re going to swim, stay minimalist about what you’re putting on your skin and hair. Additionally, think about where you are going to get in and out — rock or sandy areas are preferable to vegetation that will get trampled. 

Before you get in, be sure there’s an outflow if the lake is smaller. Pools of water with no outflow can sit without being refreshed by snow melt until the following year.

Plan for low core temperature

There’s no warm shower available next to an alpine lake. Our core temperatures are slow to adjust, and as you come out of a mountain lake you may find you’re cold for a while. I like to change into dry, warm clothes, with additional layers and black clothing on sunny days. Some people like to drink a warm beverage, but it’s worth noting that although it will feel warm and comforting it actually does little to warm your core. When I get extremely chilled, I get into my sleeping bag until I feel better. Also, remember that even if you’re cold, swimming can be a workout and you should plan to drink water, too.

Gear can help… but isn’t necessary

Wetsuits are pretty annoying to pack up to a lake and folding them or stuffing them into a backpack can damage the neoprene. Some better options include a neoprene bonnet/swim cap and neoprene thermal socks or gloves. These pack well! I’ve also noticed it’s helpful to have different goggles for outdoor swimming than for indoors because of the very different light levels and colors. I opt for more grey tinted, sunglass-like goggles for days when the sun is shining.

Get out there and enjoy some crystal clear waters this summer! You can find lakes to hike to in our Hiking Guide