DD (Dust Devil) Intensity Scale

DD 0
10-30 mph (16-48 kph) 8-26 knots
Breeze whirlwind = no resulting damage: loose litter blown around, leaves and light paper raised into the air, tall grass rustles, loose dust lofted into the funnel, umbrellas and tents somewhat disturbed. Typical path width 3-10 feet, whirlwind duration up to 7 minutes.

DD 1
31- 54 mph (49-86 kph) 27- 47 knots

Gale Whirlwind = negligible damage: light litter spirals in the air. Tents, umbrellas, seriously disturbed; Untethered tents blown around patio umbrellas blown about, most exposed tiles, slates on roofs dislodged. Empty household trash cans, recycle bins, blown over, considerable amounts of loose dust sucked up high into the funnel, light litter sucked up high into the air, heavy litter blown about the ground, Twigs snapped; trail visible through crops and short grass sports fields. Possible risk of injury from flying patio umbrellas. Typical path width 10-100 feet, whirlwind duration up to 15 minutes.

DD 2
55-73 mph (87-119 kph) 48-63 knots

Storm Whirlwind = light damage: deckchairs, small flower pots, tents, patio umbrellas, and heavy litter become airborne. Tents, trampolines, and bouncy houses, lofted high into the air, Empty wheelie Bin trash cans blown over, Minor damage to tin sheds, cedar panel fences damaged or in some cases flattened. Minor damage to hedges and trees, Weak branches break off trees, and loose plywood sheets 1/2” and thinner blown around. Considerable risk of injury from flying trampolines, bouncy houses, plywood and umbrellas. Typical path width 15-150 feet, whirlwind duration up to 20 minutes.

DD 3
74-95 mph (120-153 kph) 64-82 knots

Hurricane Whirlwind = moderate damage: empty wheelie bins, trash cans, recycle boxes, hanging baskets, flower pots become airborne. Most well built solid panel wooden fences damaged or destroyed, Full trash cans, wheelie bins, heavy flower pots blown around. mobile homes displaced, light travel trailers blown over, tin garden sheds become airborne and anchored ones destroyed, garage roofs torn away, much damage to tiled roofs and chimney stacks. Some big branches twisted or snapped off, small trees in weak sandy soils uprooted. People blown down, serious risk of injury from flying debris of all sorts. Typical path width 20-200 feet, whirlwind duration up to 30 minutes.

DD 4
96-110 mph (154-177 kph) 83-92 knots

Powerful Whirlwind = serious damage: Mobile homes overturned / badly damaged, roofs peeled off; garages and weak outbuildings destroyed; Wooden rail fences damaged, house roof timbers considerably exposed. Some of the bigger trees snapped or uprooted. Full trash cans wheelie bins become airborne. considerable risk of serious injury from falling trees and flying debris. Typical width 30-300 feet, whirlwind duration up to 45 minutes.

DD 5
111-129 mph (178-208 kph) 96-112 knots

Extreme Whirlwind = severe damage: light travel trailers blown around, destroyed
Motor cars, heavy pontoon boats, large steel trash dumpsters, and people themselves levitated. Mobile homes torn apart / destroyed; sheds airborne for considerable distances; entire roofs removed from some houses; roof timbers of stronger brick or stone houses completely exposed; gable ends torn away. Numerous trees uprooted or snapped. Wooden rail fences destroyed, chain link fences damaged by flying debris. Extreme risk of serious injury or death from flying debris, trees blowing over, and being sucked up into the funnel itself. Typical path width 40-400 feet, whirlwind duration up to 1 hour.

Quick facts:
the typical dust devil lasts seven minutes, ranges from three to fifteen feet in diameter, and has winds ranging from 15-25 mph (25-40 km/h).
Exceptional Dust Devils Can:
Turn invisible when traveling across wet ground
Race along the ground as fast as 62 mph (100kph)
Have winds in excess of 95 mph (152 km/h)
Grow as large as 300 meters, 1000 feet wide
Extend over 2000 feet into the atmosphere
March side by side in pairs
Generate 100.000 volts of static electricity
Lift tones of dust/sand into the funnel

That said dust devils lift more dust into the atmosphere per year than sandstorms and can be initiated by something as simple as a car traveling down the freeway.
Not only that on may 6, 2015 a small town in western Canada called Invermere got struck with a tornadic dust devil that reached an intensity never seen before. The whirlwind was so vicious it tore branches off trees, damaged the roof on an industrial building and most shockingly of all tossed two 1500 pound pontoon boats straight through a chain link fence like it was nothing. According to one witness the dust devil was originally spawned by a semi truck barreling down the highway. Considering the fact that two 1500 pound boats each strapped down to a 700 pound flat-deck trailer where sucked into the air and thrown with such force they took out a 6 foot tall chain link fence indicates this particular dirt devil packed winds over 115 miles per hour thus earning DD 5 on the dust devil intensity scale.

CaptureInvermere Canada record Dust Devil Damage

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