EOSC 114: Hurricanes Learning Goals
EOSC 114: Hurricanes Learning Goals 1. Be wary of the main storm hazards.
2. Recognize thunderstorms, be able to identify thunderstorm components, and and explain how they evolve.
3. Explain how storms get their energy from the Sun.
4. Explain the main characteristics that make a supercell thunderstorm so much nastier than a normal thunderstorm. 5. Be able to recognize thunderstorms in radar and satellite images.
6. Describe the different types of lightning, how they form, and what happens when they strike something.
-lightning -hail -downpours -local flooding, storm surges -downbursts -gustfronts Move from southwest to northeast -anvilsign of thunderstorm at top, like a protrusion; top of troposhphere -overshooting top above anvil -mammatus cloudsunder anvils of some thunderstorms, but also on non-dangerous clouds…useless for identifying -main updraftmain part of the storm, where air is uplifted -wall cloudcloud that is between main thunderstorm and tornado Sunwarms water warm air updrafted air parcelswindblown (advected) air parcelwarm air cools in storm, releases latent heat as sensible heatcondensation powers downdrafts -long lasting -violent wind gusts -cause tornadoes and hail -severe -Orographic thunderstorm: form over mountains, can cause flash floods -Multicell thunderstorm: clump of multiple cells -Squall Line thunderstorms: long line of heavy rainfall thunderstorms -Air Mass thunderstorms: only need heat from hot ground, don’t need to form on fronts -Supercell: if mesocyclone, rotation visible -Inter-cloud (IC) -Cloud-Ground (CG) positive-->less frequent, stronger, formed from anvil (further distance, must be stronger), more likely to cause wild fires negativemore frequent, not as strong, formed from main cloud (base), Stepped leader is first unseen path of lightning that meets with streamers from tall objects. After, the return stroke (visible part) strikes again, creating thunder.
7. Explain the behavior of downbursts and
Lightning Alleys: Florida (US) & Ontario (CA) Downbursts: rapid fall of cool air due to
EOSC 114: Hurricanes Learning Goals gust fronts, and identify their associated cloud & dust features.
precipitation dragging air down +evaporation as it falls, cooling air
8. Describe why the fact that "cold air holds less water vapour than warm air" is critical in explaining how thunderstorms can extract energy from humid air 9. Recognize mammatus clouds and the flanking line, and describe their relationship to thunderstorms.
Gust front: after downbursts hit ground, air moves fast horizontally, called gust front. gust front over dust = haboob (dust/sand storm) gust front pushing up humid air = arc cloud Warm air rises to thunderstorms, and cools on the way. Once it reaches its dew-point temp, condensation occurs, releasing latent heat. This latent heat is the energy for storms. Mammatus cloudsunder anvil in thunderstorm clouds, also in non-dangerous clouds; not used for identifying
10. Explain how vertical and horizontal winds are created by heat released in storms.
11. Explain what the continuity effect is, and how it ties vertical and horizontal motions into circulations
12. Describe rain and hail hazards of thunderstorms, and state actions you can take to be safe near thunderstorms.
13. Be able to recognize tornadoes and wall clouds.
Flanking lineline of clouds behind mature cell, still in cumulus stage. Winds help grow these new cells into mature stage; in multicell, squall line thunderstorms Temperature affects both vertical & horizontal winds: -Vertical windsdue to buoyancy, which is due to density, which is due to temperature (warmer airless denserises, more buoyant) -Horizontal windsdue to pressure gradient, which is due to temperature (warmer air expandmore pressurepush outward) Continuityie air is continuous, so air molecules fill gaps made by other moving molecules. This causes circulation as molecules fill in gaps left at base, as air rises up. Hail: large pieces of ice, can cause major damage… cars, building, crops, etc. Occur when ice crystals fall in updraft instead of downdraft region Action- get inside, under solid cover Rain: Occur when ice crystals fall in downdraft region and melt due to warmer air; can cause landslides, flash floods, reduced driving visibility Action- move to higher ground Tornadoes: rotating air columns that come from mesocyclones (supercells) funnel cloud: water droplets nearer to base of storm debris cloud: debris rotation by ground
EOSC 114: Hurricanes Learning Goals 14. Explain why supercell thunderstorms spawn the most dangerous tornadoes.
15. Relate the Enhanced Fujita scale to different amounts of damage.
16. Describe safety procedures near tornadoes. 17. Identify the times and places for high tornado risk. 18. Identify the components of a hurricane.
19. Explain how hurricanes get and utilize heat energy, and why hurricanes can exist for weeks.
Supercells that rotate (mesocyclones) have rotating winds, with a wall cloud that rotatestornado we see is only part of it; the rest is hidden in the storm Weaker tornadoes: waterspouts, landspouts,gustnadoes F0-little damage to shingles F1-trees uprooted F2-houses off foundations F3-severe,house mostly destroyed F4-devestating, chunks of large buildings gone F5-total destruction Get below ground in safe rooms w/reinforced concrete;if outside, get in ditch or hole, out of “line of fire” of rotation & swept up objects Tornado alleys: USAKansas,Oklahoma&Texas Canada-Ontario by great lakes -Eye (very low pressure) -Eye wall (ring of thunderstorms) -Spiral Bands Adiabatic coolingdry rate = 9.8C/km Once mixing ratio r reaches rS,(at LCL level, cloud base for cumulus) air has reached max humidity saturation capacity and will condense if it rises further. Condensation will occur on dust particles, causing rain and latent heat release. After LCL height, air parcel keeps rising at different moist rate that varies. The rising of air will cause a vacuum at bottom of storm, where new warm air is sucked in to fill the void. At the top, there is more pressure b/c air expanded, so air “spills” over and moves back down. This causes circulation of air, and positive feedback cycle ensues. Constant intake of warm air cycling = hurricane lasts for weeks.(see 10&11)
20. List the requirements for hurricane existence, describe how hurricanes evolve, and what causes them to die.
Also, gust fronts & downbursts can push new air up to spawning daughter storms -Warm ocean water at least 26 degrees, and 60m deep water -Coriolis effect Generates fuel with low-pressure eye by warming boundary layer air (evaporated water + wave sprays) = very humid Continuous flow of air into core (eye + eye wall) and out is due to low pressure at base
EOSC 114: Hurricanes Learning Goals and high pressure at top
21. Describe the risks associated with hurricanes, and appropriate safety procedures.
Hurricanes die out if they run out of warm fuel (ie. go over cold waters or land), run into the equator (no coriolis effect) -Sea-level rise + storm surge Action: don’t live on beaches of southeast USA, and have plan to evacuate to higher ground
2. Recognize thunderstorms, be able to identify thunderstorm components, and and explain how they evolve.
3. Explain how storms get their energy from the Sun.
4. Explain the main characteristics that make a supercell thunderstorm so much nastier than a normal thunderstorm. 5. Be able to recognize thunderstorms in radar and satellite images.
6. Describe the different types of lightning, how they form, and what happens when they strike something.
-lightning -hail -downpours -local flooding, storm surges -downbursts -gustfronts Move from southwest to northeast -anvilsign of thunderstorm at top, like a protrusion; top of troposhphere -overshooting top above anvil -mammatus cloudsunder anvils of some thunderstorms, but also on non-dangerous clouds…useless for identifying -main updraftmain part of the storm, where air is uplifted -wall cloudcloud that is between main thunderstorm and tornado Sunwarms water warm air updrafted air parcelswindblown (advected) air parcelwarm air cools in storm, releases latent heat as sensible heatcondensation powers downdrafts -long lasting -violent wind gusts -cause tornadoes and hail -severe -Orographic thunderstorm: form over mountains, can cause flash floods -Multicell thunderstorm: clump of multiple cells -Squall Line thunderstorms: long line of heavy rainfall thunderstorms -Air Mass thunderstorms: only need heat from hot ground, don’t need to form on fronts -Supercell: if mesocyclone, rotation visible -Inter-cloud (IC) -Cloud-Ground (CG) positive-->less frequent, stronger, formed from anvil (further distance, must be stronger), more likely to cause wild fires negativemore frequent, not as strong, formed from main cloud (base), Stepped leader is first unseen path of lightning that meets with streamers from tall objects. After, the return stroke (visible part) strikes again, creating thunder.
7. Explain the behavior of downbursts and
Lightning Alleys: Florida (US) & Ontario (CA) Downbursts: rapid fall of cool air due to
EOSC 114: Hurricanes Learning Goals gust fronts, and identify their associated cloud & dust features.
precipitation dragging air down +evaporation as it falls, cooling air
8. Describe why the fact that "cold air holds less water vapour than warm air" is critical in explaining how thunderstorms can extract energy from humid air 9. Recognize mammatus clouds and the flanking line, and describe their relationship to thunderstorms.
Gust front: after downbursts hit ground, air moves fast horizontally, called gust front. gust front over dust = haboob (dust/sand storm) gust front pushing up humid air = arc cloud Warm air rises to thunderstorms, and cools on the way. Once it reaches its dew-point temp, condensation occurs, releasing latent heat. This latent heat is the energy for storms. Mammatus cloudsunder anvil in thunderstorm clouds, also in non-dangerous clouds; not used for identifying
10. Explain how vertical and horizontal winds are created by heat released in storms.
11. Explain what the continuity effect is, and how it ties vertical and horizontal motions into circulations
12. Describe rain and hail hazards of thunderstorms, and state actions you can take to be safe near thunderstorms.
13. Be able to recognize tornadoes and wall clouds.
Flanking lineline of clouds behind mature cell, still in cumulus stage. Winds help grow these new cells into mature stage; in multicell, squall line thunderstorms Temperature affects both vertical & horizontal winds: -Vertical windsdue to buoyancy, which is due to density, which is due to temperature (warmer airless denserises, more buoyant) -Horizontal windsdue to pressure gradient, which is due to temperature (warmer air expandmore pressurepush outward) Continuityie air is continuous, so air molecules fill gaps made by other moving molecules. This causes circulation as molecules fill in gaps left at base, as air rises up. Hail: large pieces of ice, can cause major damage… cars, building, crops, etc. Occur when ice crystals fall in updraft instead of downdraft region Action- get inside, under solid cover Rain: Occur when ice crystals fall in downdraft region and melt due to warmer air; can cause landslides, flash floods, reduced driving visibility Action- move to higher ground Tornadoes: rotating air columns that come from mesocyclones (supercells) funnel cloud: water droplets nearer to base of storm debris cloud: debris rotation by ground
EOSC 114: Hurricanes Learning Goals 14. Explain why supercell thunderstorms spawn the most dangerous tornadoes.
15. Relate the Enhanced Fujita scale to different amounts of damage.
16. Describe safety procedures near tornadoes. 17. Identify the times and places for high tornado risk. 18. Identify the components of a hurricane.
19. Explain how hurricanes get and utilize heat energy, and why hurricanes can exist for weeks.
Supercells that rotate (mesocyclones) have rotating winds, with a wall cloud that rotatestornado we see is only part of it; the rest is hidden in the storm Weaker tornadoes: waterspouts, landspouts,gustnadoes F0-little damage to shingles F1-trees uprooted F2-houses off foundations F3-severe,house mostly destroyed F4-devestating, chunks of large buildings gone F5-total destruction Get below ground in safe rooms w/reinforced concrete;if outside, get in ditch or hole, out of “line of fire” of rotation & swept up objects Tornado alleys: USAKansas,Oklahoma&Texas Canada-Ontario by great lakes -Eye (very low pressure) -Eye wall (ring of thunderstorms) -Spiral Bands Adiabatic coolingdry rate = 9.8C/km Once mixing ratio r reaches rS,(at LCL level, cloud base for cumulus) air has reached max humidity saturation capacity and will condense if it rises further. Condensation will occur on dust particles, causing rain and latent heat release. After LCL height, air parcel keeps rising at different moist rate that varies. The rising of air will cause a vacuum at bottom of storm, where new warm air is sucked in to fill the void. At the top, there is more pressure b/c air expanded, so air “spills” over and moves back down. This causes circulation of air, and positive feedback cycle ensues. Constant intake of warm air cycling = hurricane lasts for weeks.(see 10&11)
20. List the requirements for hurricane existence, describe how hurricanes evolve, and what causes them to die.
Also, gust fronts & downbursts can push new air up to spawning daughter storms -Warm ocean water at least 26 degrees, and 60m deep water -Coriolis effect Generates fuel with low-pressure eye by warming boundary layer air (evaporated water + wave sprays) = very humid Continuous flow of air into core (eye + eye wall) and out is due to low pressure at base
EOSC 114: Hurricanes Learning Goals and high pressure at top
21. Describe the risks associated with hurricanes, and appropriate safety procedures.
Hurricanes die out if they run out of warm fuel (ie. go over cold waters or land), run into the equator (no coriolis effect) -Sea-level rise + storm surge Action: don’t live on beaches of southeast USA, and have plan to evacuate to higher ground
