When you are spotting storms, you should be aware of the local environment at all times. You should try to keep a 2 mile buffer zone between the storm and yourself just in case the storm decides to take an unexpected turn. Keep a close and careful eye to the sky so that you can make sure no unexpected surprises could be developing, like a tornado. If you get within that 2 mile buffer zone, try to have an escape route planned just in case severe weather does develop.
When you are out, keep in mind that lightning is the number 1 killer in severe thunderstorms. During a typical year, lightning kills more people then hurricanes, tornadoes, and winter storms. The two main things that are the killer in lightning storms is that the lightning can have intense heat (over 15,000 degrees Celsius) and it can have an extreme current of over 30,000 amperes. If the spotter has to venture outside of the vehicle during severe lightning storms, he or she must remember to stay low and not go into a high risk area of getting struck by lightning. The spotter should crouch real low if he/she must venture outside of the vehicle so that they do not become a prefered target for lightning.
One thing that isn't life threatening but is the costliest weather element to the United States alone is hail. Hailstorms in the United States cause over 1 billion dollars in damages to property. Most of this damage is primarily done to crops, livestock, and roofs. Hailstones greater then 2 inches in diameter can reach up to speeds greater than 100 miles per hour as they fall to the earth. At this speed and size, a hail stone hitting a human being can be fatal, so all spotters should be aware if hail gets this big, they should take cover immediately. Although hailstones bigger than golfballs can damage the windshield of your vehicle, the best place for a spotter to be during a hailstorm is inside a vehicle.
Probably the most under rated threat caused by a thunderstorm is the downburst.
A downburst is a strong downdraft from the thunderstorm is an ourush of damaging winds on or near the earth's surface.
Downbursts are responisble for wind shear which is a sudden change in wind direction.
This wind shear is the cause of many airplane crashes in the 1970's and 1980's.
Many people cannot believe that these winds can cause as much damage as they do, they actually thought a tornado had ripped through their area.
Downbursts winds can gust as strong as 130 miles per hour and are capable of doing as much damage as a medium size tornado.