Follow National Weather Service Severe web page with current and timely Weather Warnings, Watches, and advisories on the Boulder National Weather Service page at: forecast.weather.gov/hazards/?wfo=bou
(from NOAA Severe Weather Safety page: http://www.crh.noaa.gov/bou/awebphp/svrsafety.php)
This is issued when a tornado is indicated by the WSR-88D radar or sighted by spotters; therefore, people in the affected area should seek safe shelter immediately. They can be issued without a Tornado Watch being already in effect. They are usually issued for a duration of around 30 minutes. A Tornado Warning is issued by your local National Weather Service office (NWFO). It will include where the tornado was located and what towns will be in its path. If the tornado will affect the nearshore or coastal waters, it will be issued as the combined product--Tornado Warning and Special Marine Warning. If the thunderstorm which is causing the tornado is also producing torrential rains, this warning may also be combined with a Flash Flood Warning. If there is an ampersand (&) symbol at the bottom of the warning, it indicates that the warning was issued as a result of a severe weather report. After it has been issued, the affected NWFO will followed it up periodically with Severe Weather Statements. These statements will contain updated information on the tornado and they will also let the public know when warning is no longer in effect.
This is issued by the National Weather Service when conditions are favorable for the development of tornadoes in and close to the watch area. Their size can vary depending on the weather situation. They are usually issued for a duration of 4 to 8 hours. They normally are issued well in advance of the actual occurrence of severe weather. During the watch, people should review tornado safety rules and be prepared to move a place of safety if threatening weather approaches. A Tornado Watch is issued by the Storm Prediction Center (SPC) in Norman, Oklahoma. Prior to the issuance of a Tornado Watch, SPC will usually contact the affected local National Weather Forecast Office (NWFO) and they will discuss what their current thinking is on the weather situation. Afterwards, SPC will issue a preliminary Tornado Watch and then the affected NWFO will then adjust the watch (adding or eliminating counties/parishes) and then issue it to the public. After adjusting the watch, the NWFO will let the public know which counties are included by way of a Watch Redefining Statement. During the watch, the NWFO will keep the public informed on what is happening in the watch area and also let the public know when the watch has expired or been cancelled.
Do you know what to do if a tornado is moving your way? This page contains safety guidelines to use at home, work, at school or when travelling. Remember: the greatest threat from tornadoes is windblown debris! In Your Home... The safest spot is in your basement if you have one. Get under a sturdy workbench, table or under the staircase. Stay out of the corners, as that is where debris will collect. If you do not have a basement, seek shelter on the lowest floor in an interior small room or hallway. Bathrooms and closets are good examples of rooms to go to for shelter. Get away from your windows! Strong winds with a tornado thunderstorm can shatter your windows and severely injure you. In Your Vehicle... Abandon your vehicle. Seek shelter in a dry ditch, ravine or low spot. Underneath an overpass is another possible shelter. Crouch low and cover your head with your hands. NEVER try to outrun a tornado with your vehicle. Some tornadoes can travel 60 mph! In Mobile Homes... Leave your mobile home and seek shelter in a sturdy building. If one is not available, crouch low in a dry ditch, ravine or culvert and cover your head with your hands. In High Rise Buildings... You may not have time to go to the lowest floor, so seek shelter in a hallway or small room at the center of the building. Stay away from the windows, and out of elevators! In Nursing Homes, Schools, Hospitals, and Shopping Centers... Go to your pre-designated shelter. Interior hallways or small rooms on the lowest floor are usually your best choice. Be sure to stay away from large windows or glassed areas. Do not seek shelter in dining halls, gyms or other large rooms, as roofs in these parts of a building are usually weaker. All Areas... Prepare a tornado plan. Make sure everyone knows where to go in the event of a tornado. Conduct periodic tornado drills. Assemble a disaster supply kit for emergencies. Include a first aid kit, battery powered radio and flashlight with extra batteries, canned food and can opener, and bottled water. Learn where to get weather information, and the meaning of tornado watches and warnings!
Stay alert to changing weather conditions. It does not have to be raining for lightning to be a threat. Many people are struck before the rain begins at their location. Employ "flash to bang". Sound travels one mile every 5 seconds. When you see the lightning count the seconds until you hear thunder. If 5 seconds elapse, the thunderstorm is one mile away. Ten seconds equals two miles. What is the "safe" distance from lightning? There is no absolute rule, but consider taking prompt, protective action if lightning is occurring within 3 miles of your location. Be aware that lightning can strike the ground 10 or more miles away from the thunderstorm! Avoid being the tallest object, and stay away from other tall objects such as isolated trees. Get off farm equipment, golf carts or other open vehicles. A hard top car with the windows shut is a relatively safe refuge. If hiking in the mountains, go early in the day, before thunderstorms develop. If caught in the mountains during a lightning storm, seek shelter in a deep cave, or canyon, or below treeline in a large group of trees. Beware of flash flooding. In a thunderstorm, get away from metal fences at ball fields. Drop metal objects such as golf clubs, and backpacks. Remember: metal is a very good electrical conductor! Lightning may be ready to strike near you if you feel your hair stand on end or your skin tingle. Crouch down or drop to your knees, but do not lie flat on the ground. The safest place in a lightning storm is inside a sturdy structure (your home, store etc.) Get inside the building, but do not stand by open windows, doors or patios during a thunderstorm. Unplug unnecessary appliances and stay off the phone, and out of the shower during the storm.
(From NOAA www.lightningsafety.noaa.gov/overview.htm)
There is no safe place outside when thunderstorms are in the area. If you hear thunder, you are likely within striking distance of the storm. Just remember, When Thunder Roars, Go Indoors! Too many people wait far too long to get to a safe place when thunderstorms approach. Unfortunately, these delayed actions lead to many of the lightning deaths and injuries in the U.S.
The best way to protect yourself from lightning is to avoid the threat. You simply don’t want to be caught outside in a storm. Have a lightning safety plan, and cancel or postpone activities early if thunderstorms are expected. Monitor weather conditions and get to a safe place before the weather becomes threatening. Substantial buildings and hard-topped vehicles are safe options. Rain shelters, small sheds, and open vehicles are not safe.
A safe shelter from lightning is either a substantial building or a enclosed metal vehicle. A safe building is one that is fully enclosed with a roof, walls and floor, and has plumbing or wiring. Examples include a home, school, church, hotel, office building or shopping center. Once inside, stay away from showers, sinks, bath tubs, and electronic equipment such as stoves, radios, corded telephones and computers. Unsafe buildings include car ports, open garages, covered patios, picnic shelters, beach pavilions, golf shelters, tents of any kinds, baseball dugouts, sheds and greenhouses.
A safe vehicle is any fully enclosed metal-topped vehicle such as a hard-topped car, minivan, bus, truck, etc. While inside a safe vehicle, do not use electronic devices such as radio communications during a thunderstorm. If you drive into a thunderstorm, slow down and use extra caution. If possible, pull off the road into a safe area. Do not leave the vehicle during a thunderstorm. Unsafe vehicles include golf carts, convertibles, motorcycles, or any open cab vehicle.
If someone is struck by lightning, they may need immediate medical attention. Lightning victims do not carry an electrical charge and are safe to touch. Call 911 and monitor the victim. Start CPR or use an Automated External Defibrillator if needed.
Remember...it does not have to be raining at your location for flooding to occur! If you are along a stream moving out of the mountains be aware of thunderstorms and lightning in the higher elevations upstream from your location. Never camp on low ground next to mountain streams. Do not cross flooded roadways in vehicles or on foot. It only takes 6 to 12 inches of moving water for most vehicles to become buoyant. Also, the road bed may be washed out under the water. If your vehicle stalls, abandon it immediately, and move to higher ground. Flooding is most frequent during the evening hours. Be very cautious after dark when it is more difficult to recognize the flood dangers. Get out of areas subject to flooding, including low spots, canyons, dry washes etc. If you are advised to evacuate by local authorities, do so immediately! Do not allow children to play around high water or storm drains. Stay abreast of the latest weather information by listening to NOAA Weather Radio, commercial radio and/or television.