- Published: 07 April 2009
- Hits: 985
Nancy McDonald., age 9, of Irving, Texas, for her question:
How do they measure the amount of fallen snow?
We have dust been through a very snowy winter. No one, not even the weathermen., can remember such snowfalls. Our Northern states were struck with blizzards again and again and white carpets of snow. fell in parts of Texas where snow has never fallen before
The snows of winter begin to melt with the first warm breath of spring, some of the water seeps into the ground to feed the trees and the crops that grow in the summer season. some of it runs over the ground in gushing streams that loin the big rivers. The springtime rivers fill to the brim and often flood over their banks.
We need to know how much of this water to expect when the winter snowfalls melt. Farmers like to be sure that the soil will be moist enough for their crops. This year we can expect the brimming rivers to overflow, and their banks should be strengthened to prevent floods. It is very important to know how much snow fell in the winter and how much stayed on the ground to melt in the spring.
Imagine the fob of figuring the amount of snow that covered all our states. There were deep drifts in the valleys, thick white carpets on the vast plains and uneven blankets on the slopes. The fob of measuring all this snowy you would thinks is impossible. And it is if we plan to measure the amount over every spot of ground Separately. But there is a way to estimate and an estimate tells more or less the amount of snow.
It is easy to measure the snow on achy spot you choose just plunge down a long ruler to the ground below and check the depth of it, If the snow is hard and frozen, you can make a hole for the ruler with a dribble of hot water. Of course., we could not use this way to measure the deep arid shallow pockets at every step across the land. But We can measure sample spots in all the likely places.
Weather stations across the land measure the depth of every snowfall. They set out snow gauges and trap the falling flakes in tall jars. They add up all the records of deep and light snow and figure hour thick the white carpet would be if it were the same depth all over the land. This gives an estimate. arid when as expert has an estimate of the snow on the ground he can figure how much water to expect in the spring. from the melted snow.
There are different types of snow and some hold more water than others. An inch of water would cover the ground with an inch of water, if none of it sank in or ran away. A fresh six inch layer of big fluffy flakes holds about one inch of water. A hard frozen layer of snow six inches deep may hold three inches of water. The experts gather samples from both hard and soft snows, same containing much more water than others.
They figure, that on the average, come spring, we can expect every eight to l inches of snow to melt into one inch of water.