At any given moment, there are 1,800 thunderstorms in progress in various places on Earth. And, with recent thunderstorms the area has experienced -- more to come in current forecasts -- concerns about lightning safety rise.

In the United States alone, more than 73 deaths a year occur because of lightning. Lightning is the second most weather-related killer, behind only floods.

But what exactly is lightning?

According to the National Oceanic and Atmospheric Administration's Web site, ice is a key factor in the formation of lightning. When two, weather fronts of varying temperatures meet, the air around them rises and sinks because of changing temperatures.

Various-sized ice crystals in the storm clouds collide due to that movement.

These collisions as well as the movement of air, cause the electrically charged particles of air in the cloud to separate. Positively charged crystals rise to the top for the storm and the negatively charged drop to the middle and lower parts of the storm. Enormous electrical charge differences develop.

Also, a moving storm collects a pool of positively charged particles of air that travel along the ground with the clouds, running up tall objects such as trees, houses, telephone poles and even people.

The negative particles of air at the bottom of the storm then begin to send out charges toward the ground, the administration's Web site explains.

Within a split second these negative particles -- invisible to the human eye -- move toward the positively charged objects on the ground. This meeting of negative and positive particles is seen as lightning.

That meeting heats air around it very rapidly to 30,000 degrees. This rapid expansion of heated air in turn causes thunder.

So, how can you protect yourself from lightning this storm season? The administration offered these tips for safety.

When outdoors, it is wise to postpone activities promptly when you see warning signs of a storm. For example, when skies are clear, there is a 30-second rule. Once you see lightning in the sky, count until the time you hear thunder. If that time is 30 seconds or less, the storm is within six miles and you are in danger. Seek shelter as soon as possible, the administration warns.

Lightning can strike up to 10 miles away from the rain in a storm, so even when lightning is not seen, it is a good idea to seek shelter.

It is also wise to wait 30 minutes after the last flash is seen before leaving shelter, they advised.

Also follow the precautionary tips provided to ensure a safe storm season.

Lightning safety tips

To accompany lightning safety story (mfinley)

During a lightning storm it is also wise to follow these NOAA tips: