Ice Travel

Each northern fall brings the time of travel on newly-frozen lakes and rivers, and the question of how thick must the ice be. A general lack of reported measurements on ice thickness for safe travel suggests that successful ice travelers do not measure the ice thickness very often, and unsuccessful ones are too busy to add to the public data pool.

Nevertheless, one can be safe traveling across ice at low speed in a heavy vehicle by following a simple rule given by ice-travel expert Phil Johnson of Fairbanks. Do not venture out unless the thickness of the ice in inches is five times the square root of the vehicle weight in tons. Hence a 2- ton vehicle needs seven inches of ice, and a 4-ton vehicle needs ten inches.

More complex methods are available to compute the load-bearing ability of fresh water ice under various conditions. These methods, and some very useful hints on ice travel, are contained in a new document entitled, "A Guide for Operating Cars and Light Trucks on a Floating Ice Sheet." It is available from Phil Johnson Engineering, 1045 Lakeview Terrace, Fairbanks, Alaska 99701.