Explain why it is much more difficult to measure snowfall amounts than rainfall amounts, and describe the instruments commonly used to measure snowfall amounts

Question

What will be an ideal response?

Answer 1

ANSWER: Snow is challenging to measure, since accumulations can vary greatly from one spot to the next, especially when winds are strong. Traditionally, the depth of snow in a region is determined by measuring its depth at three or more representative areas. The amount of snowfall is defined as the average of these measurements. Snow accumulation rates may be measured at a single site by using a snow board, a small wooden platform resting near the ground that is cleared off after each measurement. Snow depth may also be measured by removing the collector and inner cylinder of a standard rain gauge and allowing snow to accumulate in the outer tube. Automated gauges are now used in many areas to collect snowfall and measure the amount of liquid water it contains. Typically, these gauges are surrounded by one or more octagonal fences that help to block wind and produce more accurate readings. Remote sensing techniques are becoming a popular way to measure snow depth, especially where harsh winter conditions make it difficult to reach observing stations. Laser beams and pulses of ultrasonic energy can be sent from a transmitter to a snowpack, where the energy bounces off the snowpack back to the transmitter. This procedure allows the height of the snow accumulation to be measured in much the same way that radar measures the distance of falling rain from a transmitter. Snow height can also be obtained by measuring how long it takes a GPS signal to travel from a satellite to a snow field and then be reflected upward to a receiver located in the snow field.