Comments About Snowfall


The snowfall and snow on the ground maps are based on daily reports. In general, we have fewer observations for snow than for temperature or precipitation. The quality of these observations also tends to be less than for temperature or precipitation. For these two reasons, the data are not contoured. However, the raw data are plotted so that you can get a feel for how good the values are. These maps are intended to reflect the general situation of both snow fall and snow on the ground and may not fully represent conditions at a particular location.

Differences between Snowfall and Snow on the Ground:

One common question is related to the amount of water contained in snowfall. The very general rule-of-thumb is that 10 inches of snow equals 1 inch of water when melted. Unfortunately, this ratio is highly dependent on the temperature when the snow fell. A "heavy" snow that fell at or slightly above 32F may have a lower ratio (perhaps 4 to 1 instead of 10 to 1), while a light, fluffy snow that fell at 15F may have a higher ratio (perhaps 15 to 1).
In my opinion, an excellent reference on snow is:

"The Snow Booklet: A guide to the Science, Climatology and Measurement of Snow in the United States." by Nolan J. Doesken and Arthur Judson ISBN #0-9651056-1-x

The Snow Booklet is an 84 p. paperback book that contains many facts and figures about snow. It describes the importance of snow, its physical properties and climatological characteristics. Special emphasis is given to discussions and demonstrations of the problems and challenges in measuring snow and the impact that has on the climate data that we end up using. Detailed illustrated instructions are given for how to take accurate and consistent snow measurements under a wide variety of weather conditions.

The book contains 50 photographs, many in full color, more than 30 graphs and schematics, 16 maps and several cartoons. It is written in a style that should make it interesting to a wide audience such as weather observers, students, educators, managers and policy makers, scientists, and almost anyone who has a personal or professional interest in snow. The book doesn't tell everything there is to know about snow, but it does place a lot of interesting information onto a relatively few pages.

To order single copies of "The Snow Booklet", send $17.50 (which includes postage and handling costs) to:

Colorado Climate Center
Attn: Snow Booklet
Department of Atmospheric Science
Colorado State University
Fort Collins, CO 80523-1371

You can find a description and printable order form for this book from The university accepts money orders, checks, or credit cards (Visa/MasterCard). Please do not send cash.

Last Modified: November 9, 2007
Jim Angel