Brian Pedersen, age 13, of Peoria, Illinois, for his question:

How do they measure snowfall?

The weatherman may report that a recent storm dumped two or maybe even 40 inches of snow. You can check by probing its depth with a ruler. This is interesting, especially to skiers. But meteorologists need a far more precise method of measuring local snowfalls, as well as the total winter's snowfall that blankets a large portion of our continent. In spring, the snows will melt. Ve must estimate how much water will sink down to supply the crops and how much can be expected to drain into rivers and reservoirs. The immense job of estimating the yearly continental snowfall is computed from countless sample measurements.

In some cases sample drifts of medium and shallow layers are probed with long rulers. Rain gauges, sheltered with special wind screens give more accurate measurements of the snow fall per inch. The depth cores are melted and computed to give snowfall a liquid measurement comparable to rainfall precipitation. On the average, the ratio is 10 inches of snow per one inch of rainfall.