Thunderstorms are one of the most powerful and unpredictable weather phenomena a pilot can face. While they might look impressive from a distance, getting too close can expose an aircraft to extreme turbulence, windshear, hail, lightning, and even engine flameouts.
No matter the aircraft type or pilot experience, thunderstorms demand respect and proper planning.
What is a thunderstorm?
A thunderstorm is a convective weather system fueled by rising warm, moist air. When this air reaches colder altitudes, it condenses into towering cumulonimbus clouds (CBs), producing strong vertical currents, heavy precipitation, and electrical activity.
To form, a thunderstorm needs three ingredients:
moisture
instability in the atmosphere
a lifting mechanism (like terrain, fronts, or daytime heating)
Hazards associated with thunderstorms
Turbulence
Strong updrafts and downdrafts can exceed the structural limits of an aircraft. Near the core, turbulence can become severe and unpredictable—even in large jets.
Windshear and Microbursts
Sudden shifts in wind speed and direction are common around thunderstorms, especially near the surface. Microbursts are concentrated downdrafts that can severely affect performance during takeoff or landing.
Hail
Thunderstorms can produce hailstones large enough to damage windshields, dent leading edges, and destroy engines. Hail can be present even when the core of the storm is several miles away.
Lightning
While aircraft are designed to withstand lightning strikes, these can still cause electrical failures, minor structural damage, or system malfunctions.
Heavy Rain
Intense rainfall reduces visibility and can lead to instrument malfunctions like unreliable airspeed. It may also overwhelm drainage systems on runways, increasing the risk of hydroplaning.
Icing
Thunderstorms often reach into altitudes where supercooled water droplets exist, creating severe icing conditions that can affect lift and control surfaces.
Avoidance is the strategy
Thunderstorms are not to be flown through—they’re to be avoided. Here’s how pilots reduce the risk:
Use onboard weather radar to detect the most dangerous areas and avoid flying through red returns.
ATC radar assistance is helpful, but remember that controllers don’t always see the same level of detail.
Avoid the storm, not just the center. Stay at least 20 nautical miles away from the most active part of the cell, especially when updrafts are strong.
In terminal areas, delay or divert if a thunderstorm is near the airport. Don’t rush a takeoff or approach just to “beat the storm.”
Monitor METARs, TAFs, and SIGMETs carefully before and during flight. Look for terms like CB, TSRA, or TEMPO.
Flying near or through a thunderstorm isn’t about bravery—it’s about judgment. Pilots are trained to handle complex situations, but thunderstorms don’t care how many hours you have in your logbook.
Knowing what they can do, recognizing when to stay clear, and making smart decisions early are the best ways to stay safe. When in doubt, go around, delay, or divert. The sky will clear. It’s just weather.