Spotter Information

SKYWARNTM Spotter Program

Skywarn is a National Weather Service (NWS) program of trained volunteer severe weather spotters. Skywarn volunteers support their local community and government by providing the NWS with timely and accurate severe weather reports.  These reports, when integrated with modern NWS technology, are used to inform communities of the proper actions to take as severe weather threatens.  The key focus of the Skywarn program is to save lives and property through the use of the observations and reports of trained volunteers.

What does a Skywarn Spotter report?

Although all reports are welcome, the National Weather Service in Boise is particularly interested in the weather elements described below.

Weather Phenomena Call The NWS if…
Wind 50 mph or stronger
Hail 3/4 inch (penny size) or larger in diameter
Tornado Any tornado or rotating cloud
Flooding Any significant amount of water in normally dry areas
River Flooding Any river rising above their normal bank level
Heavy Rain Rain rates of 1 inch per hour or greater
And – Rain greater than 1 inch in 24 hours
Heavy Snow Call while snowing at a rate of 1 inch per hour or greater
And – Call with total snow fall if >= 1 inch accumulates when the snow ends
Low Visibilities Visibility less than 1/2 mile due to fog, dust, rain, or snow
Freezing Rain Any freezing rain

Estimating Hail Size

Hail Diameter Size
1/4 Pea Size
1/2 Mothball, peanut, USB Plug
3/4 Penny Size
7/8 Nickel Size
1 Quarter Size
1 1/4 Half Dollar Size
1 1/2 Ping Pong Ball Size
1 3/4 Golf Ball Size
2 Lime or medium sized Hen Egg
2 1/2 Tennis Ball Size
2 3/4 Baseball Size
3 Large Apple
4 Softball
4 1/2 Grapefruit
> 4 1/2 Probably a record sized hailstone for Idaho or Oregon
Freeze it, Measure it, Notify the NWS.

How Do I Become a Skywarn Weather Spotter?

The National Weather Service welcomes volunteers with an interest in severe weather spotting. Since the NWS instituted the Skywarn Program, there has been a significant decrease in the death rate due to tornadoes and other severe weather. The Skywarn program is completely voluntary. You may have the opportunity to call our office several times a season depending on the weather pattern in your neck-of-the-woods. If you agree, we may occasionally call you for a “ground truth” as to what is actually happening near your house. Most likely our phone call will be to confirm an element of potentially severe thunderstorms, like large hail, or damaging wind. Other calls may be to verify heavy snowfall or peak wind speed associated with large winter storms.

If you live in eastern Oregon or southwest Idaho and are interested in becoming a Skywarn spotter, please email

Become a CoCoRaHS Observer!

“Volunteers working together to measure precipitation across the nation.”

CoCoRaHS is an acronym for the Community Collaborative Rain, Hail and Snow Network.  CoCoRaHS is a unique, non-profit, community-based network of volunteers of all ages and backgrounds working together to measure and map precipitation (rain, hail and snow).   By using low-cost measurement tools, stressing training and education, and utilizing an interactive Web-site, our aim is to provide the highest quality data for natural resource, education and research applications.

Everyone can help, young, old, and everything in-between.  Each time a rain, hail or snow storm crosses your area, you take measurements of precipitation.  The only requirements are an enthusiasm for watching and reporting weather conditions and a desire to learn more about how weather can effect and impact our lives.

For more information about CoCoRaHS:

To become a CoCoRaHS observer: