Natural Disasters 2

tornado vs hurricane

tornado twisty on land from thunderstorn, hurricane water

what makes a hurricane a hurricane

low-pressure systems that form over tropical water, lots of thunderstorms/rotations of 74mph (trop storm at 40), going over land or cold water kills ‘em

what causes most hurricane deaths

storm surges account for 90%

when is hurricane season

June 1 to November 30, the peak of hurricane time (september), ocean is still retaining heat

hurricane locations

almost never in south atlantic (between 5 and 20 north/south lat)

what is a storm surge

storm goes to coast, sea levels rise, wind pushes water to coast,

hurricane names

there is a rotating list we follow, retired when exceptionally deadly/traumatizing

hurricane location names

atlantic/east pacific (hurricanes), pacific (typhoons), Indian/South Pacific (cyclones)

where/when are most tornados

east of rocky mountains, west of appalation, usually april-june/late afternoon on cold fontsr

cold vs warm fonts

Receding warm/advancing cold air ahead of cold/rounded, rapid life of warm moist air by an unstable cold air vs advancing warm/receding cold behind warm/angular cold air under warm air/warm air slowly over cold air

average time tornados are on the ground

5 minutes but range fro seconds to hours

average speed of tornados

10-20 mph but range from still to 60 mph

tornado watch vs warning

favorable conditions vs has been spotted on ground/radar

catagorization of tornados

Enhanced Fujita (EF) based on amount/type of wind damage

where/when hurricanes form

warm waters near equator, never in south atlantic, most between 5 and 20 degrees north and south lat, form during hurricane season

why hurricanes are increasing in intensity and frequency due to global warming

more moisture in the air/warmer ocean temps

6 ecological benefits of wildfires

burn away flammable ground and stop more destructive fires, free up nutrients in leaf piles, release seeds/germinate them, control tree disease/insects, maintain habitat for some species

Smokey the Bear is a villan

was a little too effective so fuel accumulated, causing the massive wildfires of today

3 factors that contribute to wildfires

dry fuel (like grass/leaves), oxygen in air, heat

crown fire vs surface fire

burns dead things vs burns through alive trees and things

how doe wildfires affect the ground

creates water repellent soil vaporizing oils and baking organic matter, there’s no vegetation/a waxy layer of earth/lots of ash that clogs pores

cohesion and mass wasting

soil and rock stick together to resist slope failure/mass wasting (down movement of rock cus gravity)

3 factors influence mass wasting

vegetation (roots bind soil/plants protect from erosion), climate (usually dry gets new water), earthquakes/volcanoes (triggering)

porosity vs permeability

amount of open pores in soil (high good for storing/sand) vs how easily water can move through (high good for saturation)

creep vs flow

viscous materials move slowly downslope vs gravity moves soil down

mass wasting mechanisms

fall, slide, flow

angle of repose is and what 5 effects a material’s angle

steepest relative angle where loose material doesn’t slide, can be affected by material size/shape/friction/moisture

how water content affects a materials angle of repose.

water acts as a binding at low, and lube at high

how vegetation effects a slope’s stability

increase sheer strength and reduce erosion

define shear strength

ability to resist forces that cause internal failure or sliding

why floods and mud/debris flow after fires are common

fire burns plants that absorb water/keeps together cus roots/creates hydrophobic soil

debris flow

rapid moving water/mud/trees downvally

fall vs slide vs flow vs creep

materials free fall vs moves in a coherent mass vs moves in a fluid-like way vs downslope movement of soil

list 5 ways you can tell a slope is creeping

curved tree trunks, tilted plants, exposed roots, soil ripples, parellel tension cracks

mitigate mass wasting

reduce slope steepness, improve drainage, strengthen slope materials, vegetation

how water plays a crucial role in the initiation of debris flows

lots of water can trigger slope failure, and starts movement, increases pore pressure and reducing friction

slope angle where most avalanches occur and why

38 degrees but range from between 30 and 45 degrees, steep/has high stress on snow, but not so steep where snow constantly falls off (can build up)

explain what to do if you are in an avalanche

move to the side, “swim” to stay above, create an air pocket before snow settles