Here are some reminders and tips on ice safety from the U.S. Forest Service:
Mendenhall Lake ice is never safe. The thickness is not measured or monitored by the Forest Service. Lake ice can vary in thickness due to water flowing into the lake.
Ice is thinner at the face of the glacier, the mouth of Steep Creek, near Nugget Falls, and near any running water, and surrounding icebergs.
Icebergs can roll over without warning, even when the lake is frozen. When icebergs roll, they break up the lake ice around them.
The face of the glacier is an active calving zone at all times of the year. In the winter, a calving can shatter the lake ice. Ice near the face of the glacier is also weaker due to calving and the movement of the glacier. Most reports of people falling through the ice come from the face of the glacier. Rockslides can and do break up lake ice.
It’s also important to plan. Tell a friend when and where you are going and when you plan to return. Take a selfie showing your clothing and face and send it to a friend. Wear sturdy boots and ice cleats. Carry additional safety gear, including ice picks, and a flotation vest. Dress in layers and carry extra clothing to change into if you get wet. Be sure your cell phone battery is charged. Know your own skill level. Beware of darkness. Carry a headlamp and extra batteries. Bring water and food. Travel with a buddy.