At the risk of sounding academic, we will point out that "it is intuitively obvious that thunderstorms are laden with a myriad of unacceptable environmental hazards to aviation." In simpler terms, please avoid thunderstorms while flying your plane.

But how do you do that?

The first technique is the old "see and avoid" concept. Look out of the cockpit for signs of convective activity. This is but a small list of things to look for that give evidence of convective turbulence, lightning, hail, downbursts, microbursts, and severe windshears.

*anvil cloud form approaching
* darkened color to clouds
* churning vertical clouds
* vertical clouds that are growing

The next step is to use the weather radar (if you have one) available to you while airborne.

Not every weather hazard in a thunderstorm is visible on weather radar. Since the radar is dependent on the return of reflected electromagnetic radiation, the ability of a particular hazard to reflect the beam will have a direct impact on what we can sense.

See the Federal Aviation Administration's guideline for aircraft reflectivity. 

The radar will not sense the following:

*small cloud droplets
* fog
* ice crystals
* small dry hail or graupel (granular snow pellets)

This list is significant because if you are using your weather radar to scan your flightpath for weather out of visual range (150 to 200 NM), you may paint a group of individual cells and conclude you could visually circumnavigate them. In reality, you may be facing a wall of clouds with imbedded thunderstorms. The low reflectivity of the surrounding clouds may not show up on the radar, especially at greater distances. Aviators will also not be able to paint the anvil portion of a thunderstorm since it's primarily ice crystals.

Since radar is our primary method of sensing thunderstorms, it's important to know how each type of precipitation affects what the radar shows. A chart of reflectivity from least-reflective precipitation to the most-reflective precipitation shows us that "bigger and wetter" is more reflective than "smaller and drier:"

Least: ice crystals
dry snow
dry hail
wet snow
rain
heavy rain
Most: wet hail

Depending on the precipitation type and its movement, recognizable thunderstorm patterns will show where the hazards are. It's important to know what to avoid on our radar screens.

Avoid any target with a dry intrusion (dryer air being sucked into the thunderstorm) giving it a V or U shape. There are several reasons for this. Severe thunderstorms have dry air mixing in the middle altitudes which can create an intrusion. Hail rising and descending in a thunderstorm would also appear as a missing area cutout from the storm.

Avoid any target with a hook or bow shape. Hook shapes are indicative of rotations taking place within severe thunderstorms. This is a strong clue to ground weather observers that hail and tornadoes are possible.

Avoid any target with protruding "fingers." Like a hook, a finger shows strong possibilities for tornadoes and hail.

Avoid any target with an asymmetric coloring and shapes. Remember, severe storms created by windshears aloft will tilt to one side. This gives shapes and colorings that are not even or concentric.

Avoid any target with an "arrow shape." Again, this is indicative of a storm with tilt and the possibility of severe hazardous weather.

Avoid any target with scalloped edges. Scalloped edges show turbulent motions taking place within the cloud. There is a good chance for hail here also.

Avoid any target storm with a few VIP Level 1 dots showing nearby. Hail falls many times outside of the thunderstorm. Checking the winds at altitude and correlating it to the side of the storm that hail will fall should help identify that potential hazard.

Flying Techniques to Remember

Publications from the FAA and USAF give us aviators numerous tips and techniques to help with that occasional encounter with a thunderstorm. Some of them are important enough to repeat again.

* Don't try to fly over thunderstorms. They can grow rapidly through your altitude, producing severe turbulence.

* Don't fly under the anvil where hail damage and lightning can occur.

* Don't fly into virga where turbulence is likely.

* Avoid all thunderstorms by 203 or more since lightning and hail have been known to extend that far from the clouds.

* Weather warnings are for thunderstorms defined as "severe." These storms produce ³/4-inch hail, tornadoes, or 50-knot wind gusts. There's a lot of damage that can occur in thunderstorms that are not flagged by warnings or a SIGMET (significant meteorological report).

* If you have to penetrate:

Go straight. Don't turn around.
Avoid the altitudes with temperatures of plus/minus 8 degrees Celsius.
Don't chase altitude. Hold your attitude and watch airspeed.
Use all anti-icing equipment.
Turn all lights in the cockpit on full and lock shoulder harnesses.

Conclusions