strength chart

This chart, distributed by the Maine Warden Service and published by the American Pulpwood Association, is for estimating the strength of ice on lakes that have clear, blue ice. It is not foolproof. For clear, blue ice on rivers, decrease the permissible load by 15 percent. Do not use this chart to estimate the strength of slush-ice. This chart does not refer to "parked" loads.
Ice thickness
in inches

Possible load

2 One person, on foot
3 Group of people, single file
7.5 Passenger car, 2-ton gross
8 Light truck, 2.5-ton gross
10 Medium truck, 3.5-ton gross
12 Heavy truck, 7- to 8-ton gross
15 10 tons
20 25 tons
25 45 tons
30 70 tons
36 110 tons
Always measure the thickness of the ice in several places; use the smallest thickness to determine the possible load capacity.