Tornadoes Study Notes

Tornadoes are classified as severe weather phenomena that stem from intense storms and atmospheric conditions.

Evolution:
- The surface air spirals counterclockwise into a low-pressure center.
- A warm front migrates northward gradually.
- A cold front wraps around the low-pressure center progressively, forming an occluded front.
- Cool air north of the warm front rises, while uplifted warm air overlaps cold air masses.

Maximum Intensity:
- Develops around 48 hours after initiation and can last for about 2 days or evolve to last over a week.
Weather Patterns:
- Characterized by strong counterclockwise winds, extensive cloud cover, and precipitation.
- Their shape resembles a giant comma:
- Comma Head: Associated with snowstorms, blizzards, and ice storms.
- Comma Tail: Associated with thunderstorms, tornadoes, and windstorms.

When mid-latitude cyclones impact the coastal areas of New England, they are referred to as nor'easters. Winds during these storms primarily come from the northeast.

Warm, humid air ascends, forming clouds.
Rain and ice become too heavy to remain aloft, leading to warm updrafts and strong downdrafts simultaneously.
In the late stage, warm updrafts cease, downdrafts dominate, resulting in lighter rain that eventually stops.

Single Cell Thunderstorm:
- Consists of a singular, non-rotating cell.
Supercell Thunderstorm:
- Significantly larger than single-cell thunderstorms.
- Notable for rotational motion of the upward-moving air, which can lead to the formation of powerful tornadoes.
- Exhibits complex updrafts and downdrafts, which allow for various weather phenomena to occur simultaneously.
Wall Cloud:
- Projects down from the top of the anvil cloud in a supercell.
- Forms where the updrafts are strongest, serving as the location from which tornadoes typically descend.

Tornado Development:
- Tornadoes descend from the wall cloud of a supercell storm.
- Although most tornadoes occur within supercells, only about 30% of supercells produce tornadoes.

Dimensions:
- Base diameter ranges from approximately 50 meters to 1 kilometer.
Wind Speed:
- Wind speeds vary from 100 km/h to 320 km/h.
- Forward speed of tornadoes can range from 0 to 110 km/h.
Tornado Track:
- Refers to the swath of destruction that a tornado leaves on the ground.
- Most tornadoes are short-lived; however, some can last over one hour.

Often characterized by a core tornado vortex that is about 1 kilometer wide.
Tornadoes in this region are considered more powerful than hurricanes, albeit they affect smaller areas.
Central North America is conducive to tornado development due to:
- Flat landscapes.
- Strong westerly winds.
- The interplay of warm, moist air from the Gulf and cold, dry air masses from the north and west.

During a Tornado:
- Move to a basement or an interior room.
- Protect your head using your arms or a sturdy item.
- Avoid large span buildings such as auditoriums or gyms, as they may be unsafe.

In a building:
- Seek shelter in a designated safe room, storm cellar, or basement.
- If no shelter is available, find a small interior room without windows and place as many walls as possible between you and the storm.
In a vehicle:
- Leave the vehicle immediately and find a reliable shelter nearby.
- Avoid attempting to outrun the tornado in congested areas.
Caught Outside:
- Lie down in a ditch away from streams and power lines, and cover your head.
- Do not seek shelter under overpasses or bridges due to the risk of flying debris.

1991 F5 Tornado in Kansas:
- A 45-minute warning led to the evacuation of 146 people, resulting in no deaths or injuries among evacuees.
- Several individuals chose to stay home, resulting in 13 deaths and 17 injuries.

Tornadoes, while fleeting compared to other weather phenomena like hurricanes, can unleash unprecedented destruction and require preparedness to mitigate risks effectively.