GG101 Lecture Notes - Lecture 6: Cumulonimbus Cloud, Funnel Cloud, Wind Shear
geo lesson 6
4 stages of tornados
Organizational stage
o Wind shear causes air to rotate within thunderstorm
o Strong updrafts in front of cold front, and upwelling due to latent heat of
condensation, tilt horizontally rotating air vertically
o If updraft and wind shear are strong enough, a large rotating column of air,
mesocyclone forms
o Updrafts in rear end of storm lower a portion of the cumulonimbus cloud to
form wall cloud
o Dust and debris on ground begin to swirl below the funnel
o If two rotating columns of air join the funnel cloud becomes a tornado
o Not all mesocylone and wall clouds form tornados, and tornados can form
without it
Mature Shrinking Rope
• Predictive conditions
o Northerly flow of marine tropical air from Gulf of Mexico >25 degrees o Cold dry air
from Canada
o Jet winds >240 km/h
• Locations
o MoreinUSthaninCAN
o Tornado Alley= south-central US
o CAN: central Sask and Alberta (Prairies), most common in June
Vulnerability
o Most common in U.S than any country
o Because: right combination of weather, topography and geographic location to
Document Summary
Mature shrinking rope: predictive conditions, northerly flow of marine tropical air from gulf of mexico >25 degrees o cold dry air from canada, jet winds >240 km/h. Locations: moreinusthanincan, tornado alley= south-central us, can: central sask and alberta (prairies), most common in june. billion in damage: canadian prone regions: alberta, southern ontario, southeastern quebec, Saskatchewan through southern manitoba to thunder bay: deadliest in canada: regina cyclone (regina, saskatchewan) 28 people killed. Blizzards: characterized by high winds, blowing snow, low visibility, low temperatures, canada wind needs to be greater than 40km/hour with visibility less than 1 km for at least 3 hours. Can create blizzard conditions in halifax, new york, boston, and other east coast cities. Can be more damaging than blizzards and just as dangerous. Typically occur during winter on north side of stationary or warm front where three conditions are met:
