Skywatchers

	Nipher Snow Gauge
	Snowfall is measured in several different ways. The nipher snow gauge is used to capture snow and measure its water content in millimetres. It's much bigger than either the standard rain gauge or the tipping bucket. The nipher snow gauge is mounted on a sliding metal pipe so that, as snow accumulates over the winter, the whole gauge can be raised to keep the top edge 5 feet above the surface of the snow. Why? So that snow from the ground doesn't drift into the gauge and give us false readings!
	The silver outside shield looks like an upside-down bell. That shape was chosen deliberately to reduce wind turbulence over the top of the gauge--wind might otherwise affect the amount of snow captured. Inside this shield is a copper cylinder that catches the falling snow. The copper cylinder can then be taken indoors to melt the contents. Once all the snow has melted, the water from it can be poured into a graduated cylinder and measured. On average it takes 10 mm of snow (or 1 cm) to make 1 mm of water--that's why the glass cylinder doesn't have to be as big. The actual water content of snow is important for many applications such as flood forecasting.
Weather observers track 2 other types of snowfall measurements: the amount of newly fallen snow and the total depth of all the snow on the ground. Both are measured in centimetres the old-fashioned way, with a metre-stick. To find out how snow is measured at an automatic station, follow this link.