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SKYWARN 2024 classes have come to an end. Thank you to all of our storm spotters. Recorded videos of our Basic and an Advanced class are hosted under the 'YouTube' tab.


What is SKYWARN®?

The effects of severe weather are felt every year by many Americans. In most years, thunderstorms, tornadoes and lightning caused hundreds of injuries and deaths and billions in property and crop damages.  To obtain critical weather information, the National Weather Service (NWS) established SKYWARN® with partner organizations. SKYWARN® is a citizen volunteer program with between 350,000 and 400,000 trained severe weather spotters. SKYWARN® storm spotters are citizens who form the nation's first line of defense against severe weather. These volunteers help keep their local communities safe by providing timely and accurate reports of severe weather to the National Weather Service.

Although SKYWARN® spotters provide essential information for all types of weather hazards, the main responsibility of a SKYWARN® spotter is to identify and describe severe local storms. In an average year, the the United States experiences more than 10,000 severe thunderstorms, 5,000 floods and more than 1,000 tornadoes.

Since the program started in the 1970s, the information provided by SKYWARN® spotters, coupled with Doppler radar technology, improved satellite and other data, has enabled NWS to issue more timely and accurate warnings for tornadoes, severe thunderstorms and flash floods. Storm spotters play a critical role because they can see things that radar and other technological tools cannot, and this ground truth is critical in helping the NWS perform our primary mission, to save lives and property.

The SKYWARN® Program at NWS Denver/Boulder

Across Northern Colorado, dedicated volunteers risk their personal safety to provide first-hand severe weather reports to their local officials, and the National Weather Service (NWS) in Boulder. Their reason, to help protect the lives and property of the citizens in Northern Colorado.

Being a storm spotter not only means dedication, but also training. Each spring the NWS in Denver/Boulder trains members of the public, police, fire department, emergency management, and amateur radio community, in the latest storm spotting techniques, basic weather concepts, and preparedness and planning. Typically the training is coordinated by a local group such as an emergency management agency or HAM radio operator. A NWS meteorologist serves as the guest instructor.

We ask participants to be at least 18 years of age or older but encourage younger people to help adults report severe weather in their area.

The goal of the training is to prepare the spotter to identify hazardous weather conditions, how to report that information to the local NWS, and personal safety.

There are also a number of in-person seminars scheduled. These seminars are free of charge and many are open to the public. Each seminar is approximately 1 1/2 to 2 hours in length and most often held in evening on a weekday. We ask that you pre-register for the classes in order to get a better head count on attendance. You are allowed to attend classes outside your county of residence.




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Instructions for printing your Skywarn™ certificate online
You should have attended a recent NWS Skywarn™ class and received a password from your trainer.  In the form below, enter your name as you want it to appear on your certificate and the password.  Then, click on the Create Certificate button.  A certificate with your name, and today's date will appear in the browser.  Click on File>Page Setup, delete any characters in the Header and Footer boxes, delete the numbers in each of the 4 margin boxes (the blanks will be replaced by the lowest possible settings), select Landscape, and click OK.  Then, click on your browser's print button.  If you have recently completed a Skywarn™ course, did not receive a printed certificate, and did not receive a password, please e-mail Russell Danielson.  Include your name and the date of your training.


Your Name





When to send a severe storm report?

When you can do safely, please send us a report when you observe one or more of the following:



Please include in your report, the location (town and county) and time/date that the severe weather occurred.

If you can supply a picture of the severe weather you are experiencing, please do.

  • Tornado (confirm rotation)
  • Funnel cloud (confirm rotation)
  • Hail (half-inch or larger)
    • 0.50" - Mothball
    • 0.75" - Dime/Penny
    • 0.88" - Nickel
    • 1.00" - Quarter
    • 1.25" - Half Dollar
    • 1.50" - Walnut/Ping Pong
    • 1.75" - Golf Ball
    • 2.00" - Hen Egg
    • 2.50" - Tennis Ball
    • 2.75" - Baseball
    • 3.00" - Tea Cup
    • 4.00" - Softball
    • 4.50" - Grapefruit
  • Wind damage.  What is damaged?  Number of trees down?  Are they snapped, uprooted?  Large branches, small branches?
  • Measured Winds?.  50+ MPH   Gusts over 58 MPH
  • Heavy Rainfall/or Flooding
    • 1.0"+/hour in Urban Areas
    • 1.5"+/hour in Rural Areas
    • Significant Damage
    • River/Creek Flooding or Flash Flooding
    • Include pictures if you can.  How deep is the water (use what is around you as a guide, i.e water up to the bumpers).

    When to send a winter storm report?

  • Heavy snow (snowfall rates over 1"/hour)
  • Blizzard Conditions (35 mph or stronger winds, 1/4 or lower visibility in blowing snow)
  • Dense Fog (1/4 or lower visibility)
  • Freezing Drizzle (icy/slick road surfaces)
  • Heavy snow (snowfall rates over 1"/hour)
  • Rain to Snow or Snow to Rain Changeover
  • Closed or impassable roads due to snow and wind
  • Sustained or gusts 50+ MPH/75+ MPH (plains/mountains and foothills)

    How to send us a storm report.

    1. Call the NWS Denver/Boulder Office
      For life-threatening and imminent severe weather threats, please contact our forecast office immediately (even if you also contact us by social media or email) through our 24-hour public service phone uses the 800 number you received at the spotter class or at 303-494-3210.
    2. Submit a Storm Report Online via the iNWS portal, NWS Denver/Boulder Facebook or Twitter websites.
    3. If lives and property are impacted, please call 911
    4. mPING App
    5. The Spotter Network
    6. Email
      Email us your report with images if possible – You may also pass along additional information such as delayed reports and weather and damage pictures by e-mailing them to the NWS Denver/Boulder office.
    • Tornado: A violently rotating column of air, usually pendant to a cumulonimbus, with circulation reaching the ground. It nearly always starts as a funnel cloud and may be accompanied by a loud roaring noise. On a local scale, it is the most destructive of all atmospheric phenomena.
    • Severe Thunderstorm: A thunderstorm that produces a tornado, winds of at least 58 mph (50 knots), and/or hail at least 1" in diameter. Structural wind damage may imply the occurrence of a severe thunderstorm. A thunderstorm wind equal to or greater than 40 mph (35 knots) and/or hail of at least ½" is defined as approaching severe.
    • Flash Flood: A flood which is caused by heavy or excessive rainfall in a short period of time, generally less than 6 hours. Also, at times a dam failure can cause a flash flood, depending on the type of dam and time period during which the break occurs.


Skywarn Basic and Advanced Recordings


Skywarn Basic Course in Spanish (4 parts)

This course is NOT produced by your local NWS office in Boulder.

There are two courses, including:  "Role of the Skywarn Spotter" and "Skywarn Spotter Convective Basics".

These courses cover the basics of being a Skywarn Spotter.  They are free and accessible from the METED website.

For more information contact:
Russell Danielson