How to Tell If a Lake Is Frozen

Frozen lakes are often public safety minefields due to the inability to tell how thick the ice is. While a child may safely walk across the surface, an adult may be too heavy and cause the ice to crack. In emergency situations, it is often vital to assess whether a lake is frozen enough to drive vehicles across it, or even land aircraft on it. This is an extremely tricky process done by assessing factors such as frozen bubbles, preexisting cracks, pressure ridges, dark spots or overflow.

Instructions

• 1

  Assess the surrounding environment. If there are inflows to the lake from other nearby springs, the water may be warmer and cause thinner areas of ice to appear sporadically across the lake.

• 2

  Observe the snow cover as well as the ice. If the cold weather continues, this snow could become compacted ice. If it warms up, the snow melts and heats up the surrounding ice too.

• 3

  Assess the recent air temperature and monitor it over the course of the next few days too. A rapid drop in air temperature can cause the ice to become more brittle and decrease its safety.

• 4

  Make a rudimentary guess at the ice's safety based on the sum of the ice's thickness being equal to four times the square root of the weight of the load (in tonnes) on the ice. For example, if you weigh 0.0907 tonnes (200 pounds), find the square root which, in this case, is 0.301 and multiply it by 4 to find the estimate of how thick the ice is, which in this case is roughly 1.2 inches thick.