Plane Facts: Thunderstorms

The way the Lower 48 United States are situated geographically and climatically, we get a lot of severe weather. From hurricanes lined up and rolling in from the Atlantic and Caribbean, to the twisters of Tornado Alley, right down to the severe thunderstorms marching southwest to northeast and wreaking havoc along the way, America has arguably the most diverse severe weather on the planet. While tornados and hurricanes do huge amounts of damage, in terms of sheer numbers, thunderstorms are the most destructive weather events. For pilots, well, we can see hurricanes forming a thousand miles away, and storms big enough to form tornados give ample warning, and we stay well away from them. Thunderstorms can be forecasted, but they can also pop up with little or no warning and can build to 50,000 behemoths in a matter of hours. And because they often form in lines, they are hard, if not impossible, to safely get through or around,.

Average yearly cost of severe TS damage, U.S.: $10 billion

Number of TS worldwide/year: 16 million

Average number of TS in progress at any given time, worldwide: 2,000

Number of TS U.S./year: ~100,000

Most likely time of year: Spring/Summer

Most likely time of day, Gulf Coast, Southeastern and Western States: Afternoon

Most likely time of day, Plains States: Late afternoon/Night

State with most days with thunderstorms: Florida

Average TS cell diameter: 15 miles

Average duration: 30 minutes

Average TS max wind speed: 34-40 mph

Average TS tops: 40,000 feet

Max recorded TS top: 75,000 feet

Associated aviation dangers: Lightning, turbulence, wind shear, downbursts, icing, hail, engine water ingestion, reduced visibility

Severe storm qualifications: Hail 1"+ diameter, winds 58 mph+ (50 kts), tornadic activity

Percentage of storms that classify as severe: 10%

Lightning temp: Up to 30,000Â°C (54,032Â°F)

Temperature of the Sun: 5,778K (5,505Â°C)

Lightning speed, leader: ~136,000 mph

Length of leader steps: ~150 feet

Lightning speed, return stroke (visible flash): ~62,000,000 mph

Estimated peak power, single stroke: 1,000,000,000,000 watts

Lightning fatalities, U.S., 2016: 38, 76% male

Lightning fatalities, U.S., 2006-2016: 352, 79% male

Average frequency of lightning striking an aircraft: Once every 1,000 flight hours

Most common altitudes at which lightning strikes occur: 8,000-14,000 feet

Types of lightning damage to aircraft: Puncturing fuselage, burning, melting, or distorting aircraft parts, temporary or permanent damage to avionics, fire in the fuel system

Number of U.S. aviation accidents/incidents in which lightning was a contributing factor since 1962: 62

Microburst-related danger: Extreme wind shear, powerful up/downdrafts

Microburst Causes: Mid-level dry air entrainment (mixing of environmental air into cloud causing cooling and sinking), cooling beneath the thunderstorm cloud base, sublimation, rain and/or hail within the thunderstorm (precipitation drag)

Microburst downdraft: Up to 6,000 fpm

Microburst max speed: 150+ mph

Microburst size: 2.5 miles diameter or smaller

Average duration, microburst: 5 minutes

Microburst location: Under storm

Macroburst: Microburst-type downdraft larger than 2.5 miles in diameter, can cause straight line winds resulting in tornado-like damage

Macroburst, max wind speed: 130+ mph

Macroburst, max distance: Up to 250 miles from center of downburst

TS-induced turbulence, range: Up to 20 miles laterally from storm

TS turbulence, location: In clouds or clear air

Location of strongest turbulence: In clouds between updraft and downdraft

Supercooled water droplets, most common location: In CB, 0 to -15Â°C