Why it Matters for Flying

Fieldwork Foundations

Picture this: You’re collecting B-Roll footage for an upcoming YouTube video for your channel you run to market your business. You want to collect footage of some of the territory you’ve been exploring lately.

You get all the way to your destination, an open and mountainous valley about 45 minutes away from where you’re staying. It’s sunset out, it’s gorgeous, and you know the shots you’re about to get are going to be amazing.

Unfortunately, just 10 minutes into your flight you begin to sense the wind shifting. You can see your drone is starting to be pummeled around due to turbulent air. And what’s more, a large towering cloud is forming what looks like not far from you at all.

These are tell-tail signs a thunderstorm is on its way, and you better land your sAUAS asap or risk loosing it to lightning or getting drenched in rain and crashing.

This is why this lesson teaches you the 3 stages of a thunderstorm and what the characteristic are of each one.

Lesson Focus

How Thunderstorms Form and Behave

In this lesson, you’ll learn what creates a thunderstorm—from the components that fuel them to the stages they move through. We’ll explore what to look for in the sky, what kind of turbulence or downdrafts to expect, and why storms often form in the late afternoon.

By the end, you’ll be able to recognize the signs of developing storm activity and know when to call off a flight mission/

3 Phases to Watch

Weather Foundations

Most ordinary thunderstorms follow a predictable life cycle that lasts around an hour.

Larger storm systems like squall lines and supercells last much longer and behave far more violently, but they’re built on the same basic principles.

The following are the 3 phases of a thunderstorm, and the characteristics of each.

Phase 1: Cumulus Phase

Storm Forming its Structure

This phase is all about ascent and buildup.
No rain falls yet, but the structure is forming.

The three main components of the Cumulus Phase are:

• (a) Marks the beginning of a thunderstorm’s life cycle
• (b) Vigorous Updrafts
• (c) Development of Cumulus Clouds

The Cumulus Phase (a)marks the beginning of a thunderstorm’s life cycle.

This (b)starts with vigorous updrafts—warm, moist air rising rapidly into the atmosphere. There’s no rain yet, just vertical growth. This is the storm forming its structure—gathering strength before releasing it in the next phase. The cumulus clouds signal the storm is on the move.

As the updrafts create lift, the air cools and condenses, (c)forming cumulus clouds. From the ground, it might still look peaceful—just big, beautiful clouds stacking upward. But don’t be fooled. These towering clouds are the first sign the atmosphere is building energy.

• Term to Know:
• Cumulonimbus Cloud – A towering thunderstorm cloud with strong vertical development that can eventually produce rain, lightning, and severe weather.

Phase 2: Mature Phase

Most Intense Phase

This is the most intense part of the thunderstorm’s life cycle.

• Key Traits:
• (a) Greatest intensity of the storm
• (b) Active Updrafts and Downdrafts = strong vertical movement & turbulence
• (c) Precipitation begins
• (d) Cumulonimbus cloud has fully developed
• (e) Anvil shape forms at top of cloud

In this stage, where (a)ntensity is at its peak, both (b) updrafts and downdrafts are active. Warm, moist air continues to rise, while cooler, heavier air sinks, creating strong vertical movement within the cloud. This dynamic fuels turbulence and unleashes the storm’s full power:

(c)Precipitation begins when the water droplets inside the cloud become too heavy to stay aloft and begin to fall as the downdrafts begin and increase.

From the ground, it’s obvious: skies darken, rain intensifies, and winds shift. The storm is now fully alive.

By now, the (d)umulonimbus cloud is fully developed—a towering giant that often (e)forms an anvil-shaped top. That flat, wide spread happens when powerful updrafts hit the stratosphere and flatten out.

This phase usually lasts 15 to 30 minutes, depending on the storm’s strength, before the system begins to collapse into the final stage.

Phase 3: Dissipating Phase

Marks the end of the thunderstorm’s lifecycle

As the storm runs out of fuel, updrafts slow down and eventually stop. Without warm air rising to sustain it, the storm begins to collapse in on itself.

Key Traits:

• (a) Downdrafts Increase
• (b) Updrafts Stop
• (c) Storm weakens

(a)Downdrafts increase, pushing cooler air downward and cutting off the supply of rising moisture, and (b) stopping updrafts. The (c)towering cloud structure begins to break apart as the storm weakens, losing its sharp edges and vertical shape.

Light rain may continue, but the storm’s energy fades fast. From the ground, the worst has passed—winds calm, rain softens, and the dark cloud slowly dissolves from the bottom up.

This phase marks the end of the thunderstorm’s life cycle.

While the danger has mostly passed, wet surfaces, residual winds, and reduced visibility may still affect post-storm drone operations.

Lighting

Consistently associated with thunderstorms because it results from the buildup and discharge of electrical energy within the storm clouds.

Lightning is the most hazardous circumstance when operating an sUAS in close proximity to thunderstorms because any lightning strike within the vicinity can potentially damage or destroy the drone’s electronics.

Hail

Thunderstorms can also bring hail, small balls of ice, which can hit areas far from the storm, including where you’re flying your drone. Don’t assume you’re safe just because the storm seems far away—hail, even small pieces, can damage your drone.

Turbulence

Thunderstorms are notorious for generating severe turbulence, especially in their mature stage. The intense updrafts and downdrafts within this stage can create sudden and strong changes in air movement making sUAS control difficult.

Icing

Thunderstorms at high altitudes create supercooled water droplets that freeze on aircraft surfaces, causing structural icing. Icing on drones increases weight, disrupts aerodynamics, reduces lift, and can lead to loss of control.

Microbursts

Thunderstorms can create microbursts, which are sudden, strong winds that blow downward. Microbursts can cause aircraft to drop quickly and are very dangerous during takeoff or landing.

Wind Shear

Wind shear refers to a sudden change in wind speed or direction over a short distance, either horizontally or vertically, within the atmosphere. It can occur at any altitude and is especially important during weather events like thunderstorms, where it can have a significant impact on aircraft performance and safety.

Squall Lines

(Most dangerous type of thunderstorm to aircarft)

Squall line thunderstorms are the most dangerous to aircraft because they produce severe weather such as high winds, hail, turbulence, and tornadoes.

Squall lines are often associated with cold fronts and wind shear, which contribute to their rapid intensification and potential for widespread damage, flash flooding, and dangerous flying conditions.

Tornadoes

Tornadoes can potentially develop from any cloud linked to a severe thunderstorm, even if it’s many miles from the main thunderstorm cloud.