what is nssl? established in 1964 one of 12 research laboratories in noaa only federal lab focused...
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What is NSSL?
• Established in 1964
• One of 12 research laboratories in NOAA
• Only federal lab focused on severe-weather research
• Employs 140 people in Norman, Oklahoma
• Located on North Campus at Westheimer Airport
• $15 million a year ($5.5 million in NOAA base)
NSSL Accomplishments
• Engineering and scientific research that demonstrated the importance of the nationwide WSR-88D radar network
• Continued Doppler-radar research: dual-polarimetry, phased-array
• Severe-storm structure and dynamics• VORTEX field program (tornadogenesis)• Information and decision support systems• Collocation and interaction with Storm Prediction Center
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ApplicationsApplications
UnderstandUnderstandSevereSevereWeatherWeatherProcessesProcesses
ModelingModelingStudiesStudies
ObservationalObservationalStudiesStudies
To work in partnership with the National Weather Service to enhance NOAA’s capability of providing accurate forecasts and warnings of all types of hazardous weather events (blizzards, ice storms, flash floods, tornadoes, lightning, etc.).
The NSSL Mission:The NSSL Mission:
NOAANOAAServicesServices
TheoreticalTheoreticalStudiesStudies
What Do I Do at NSSL?• Midlatitude cyclones and fronts• Improving snow & drizzle forecasting• Arizona summertime convective-storm climatology (with
Pam MacKeen)• The Intermountain Precipitation
Experiment (with Univ. of Utah)• 3 May 1999 Oklahoma tornadoes
(with Paul Roebber, UW Milwaukee) • Research Experience for
Undergraduates mentor• Adjunct Professor, Univ. of Oklahoma• 2002 Winter Olympics, NWS Forecaster• Canoe & Kayak columnist
Lightning and Lightning Safety
Ron HolleVaisala - Global AtmosphericsTucson, [email protected]
David SchultzNOAA/National Severe Storms LaboratoryNorman, [email protected]
The Lightning Hazard
• An average of 25,000,000 cloud-to-ground flashes strike the ground each year in the U.S.
• Lightning strikes the ground nearly everywhere
• As a result, specific warnings cannot be issued for every flash for each person.
stormshot.comIvan Eberle
Average Annual Storm-Related Deaths from 1966 to 1995
Floods Lightning Tornadoes Hurricanes0
50
100
150135
8573
25
Lightning Casualties by Statefrom 1959 to 1994
498
732
394
577
629
644
473
545
410
1523
A
Rank 1-1011-2021-3031-52
331 355
347296 295
306
278
360
355
250
40
26
1879
64
87
116
164
104
249
79
35
111
169 241
234 176
227
238
235
18542
8849
12630
76
108
Hawaii: 4
Alaska: 0
D. C.: 23 Puerto Rico: 36
Casualties
Lightning Casualty Rate by State from 1959 to 1994
Rank 1-10
11-20
21-3031-52B
Casualty rate
Settings of U.S. LightningDeaths 100 Years Apart
1890s Indoors most often - 23% of all deaths inside homes Next largest - outdoors and agriculture Almost no recreation and sports deaths
1990s Agriculture - much less frequent Only 2% inside houses Outdoors is largest category - employment, around
homes, other urban activities 12% of deaths under trees Sports and recreation deaths frequent - beach, water, golf, camping
Lightning Casualties by Gender
0
10
20
30
40
50
60
70
80
90
Male Female
Colorado Central Florida
Odds of Being a Lightning Victim
• 280,000,000 people in U.S.• 60 killed, 340 injured a year (official)
1 in 700,000 • 100 deaths and 900 injuries a year (likely)
1 in 280,000• Life span of 80 years 1 in 3,500• Major impact on 10 people 1 in 350
• Temperature– 50,000°F
• Power– 10,000 MegaWatts for 1/2 second
• Energy– 30,000,000 Volts
– 50,000 Amperes
• Size– 1 inch
Lightning
Necessary Conditions for Lightning Formation
• Updraft in a cumulus cloud
• Colder than freezing at top
• A mixed-phase environment with: Graupel–soft irregular hail particles Ice crystals Supercooled liquid water
Earle WiIliams, MIT, 09/98
Cumulus Towers
Ronald L. Holle©1990
Lightning
• Lightning is an electric discharge in the cloud.• Most lightning paths remain within the cloud;
others are cloud-to-ground.• From the initiation point (around 15,000 feet
during summer), the stroke travels in 50-yard steps until it reaches the ground.
• At the lower tip of each step, the leader hesitates, looking for something to strike within about 50 yards.
Streamers
• At the ground, there are small (inches to feet long) streamers reaching upward to the electrified cloud.
• When the downward leader connects to an upward streamer, the bright light called lightning is visible and moves upward.
• Charge is lowered to the ground, but current flows upward.
• Most clouds lower negative charge to the ground, but 5% lower positive charge.
Why Trees and Fences are Bad Places
Ruth Lyon-Batemen, Island Park, Idaho
When Lightning is Imminent
• hair stands on end• sparks, electrical discharges• St. Elmo’s fire• hear static discharges
8/20/75: Sequoia National Park at Moro Rock: One person killed and 8 injured, the most seriously, the photographer. All were from an extended family. Hail was falling as they were at the top, 300 feet higher and 1/3 mile away from the parking lot.
Flash-to-bang
Storm motion
5 sec. 10 sec. 15 sec..
1 mile 2 miles 3 miles
.
Flash Outside Rain Shaft
Blue Sky
• Part of the sky is often blue during lightning.
• Summer thunderstorms are vertical.
• Thunderstorms often are isolated.
• About 10% of lightning occurs without rain at the strike point.
• Pay attention to the thunder, not the blue sky or rain.
Visible Sky DuringLightning Threat
Lightning was observedfrom the dark cloudoverhead within a fewminutes of this view
Boulder, Colorado24 August 19911119 MDTToward S
Ronald L. Holle©1991
Visible Sky DuringLightning Threat
Lightning was observed 2 miles away 10 seconds before photo
Tucson, Arizona19 October 20001305 MSTToward S
Ronald L. Holle©2000
Sequence of Cloud-to-Ground Flashes in Colorado Storm
225
230
235
240
245
470 475 480 485 490 495
North-Southdistance(km)
East -West d ist ance (km)
Clust er No. 7Nort heast Colorado
Last
First
Successive flashesare within 15 kmand 5 minutes of theprevious flash
The 30–30 Rule
Most people who die from lightning are struck early in the storm or near the end.
80% of the cloud-to-ground flashes within the same storm fall within 6 miles (10 km) of the previous ground strike point. 5 seconds times 6 miles = 30 seconds
93% of successive cloud-to-ground strokes are within 5 minutes of each other, but the distribution extends out in time with quite a few lightning casualties at longer times. So, we advocate 30 minutes after the last stroke before continuing outdoor activities.
Lightning Safety Precautions
1. Avoid dangerous lightning situations
• Watch for signs of a thunderstorm that is starting to grow quickly
• Be aware of other storms in your area
• Give yourself time to reach a safe place
before lightning is an immediate threat
Lightning Safety Precautions
2. Plan Ahead
Designate a spotter who is watching for the threat of lightning
Watch for storms growing quickly before
it's too late to reach a safe place
Follow your safety plan
Lightning Safety Precautions
3. Safe places
Residence or frequently occupied building
Avoid contact with electric lines, phone lines, and plumbing. Unplug appliances before lightning arrives
Vehicle with a metal top
Avoid contact with metal parts, and antenna connections
Lightning Safety Precautions
4. Unsafe places
Shelters
Rain, sun, beach, golf, or picnic shelters
Tents
Open areas more than 100 yards across
Trees, poles, tall objects
Lightning Safety Precautions
5. Don’t be the highest object, or
connected to it
• Don't be the highest object
• Don't be connected to anything taller than its surroundings
• AS A LAST RESORT: Crouch on the balls of the feet, head down, and cover your ears with your hands.
6. Use the 30–30 rule
First 30 30 seconds = flash-to-bang before storm
Second 30 Wait 30 minutes after last flash or thunder before resuming activity
Especially critical for large groups
Lightning Safety Precautions
Lightning Safety for Groups
Virginia Tech vs. Georgia Tech(Aug. 27, 2000)
Lee Trevino, Jerry Heard and Bobby Nichols were struck by lightning during the 1975 Western Open. The incident prompted newsafety standards in weather preparedness at PGA events, but four spectators were killed when struck by lightning during the 1991 U.S. Open at Hazeltine National.
7. Special Outdoor Advice
• NO PLACE OUTSIDE IS SAFE DURING THUNDERSTORMS!
• Be off the mountains by the time afternoon thunderstorms are expected.
• Trails within the forest are only marginally safer than exposed trails.
• Remove backpacks to expedite getting to safety.
• Caves, overhangs, and pavilions only protect you from the rain, not the lightning, which can travel from the strike point to you.
Lightning Safety Precautions
When on the Water
• Get to land immediately.• Lightning strikes have killed or injured people
more than 30 yards away on water.
wildweather.com
Lightning Effects on People
• Deaths (10% of the time)The only cause is cardiopulmonary arrest
• Injuries
52% - Memory deficit
44% - Attention deficit
41% - Sleep disturbance
38% - Dizziness
. . .
Dr. Mary Ann Cooper, April 1999
First Aid for Lightning Victims
• Call 911.
• Make no more casualties by exposing rescuers to continuing lightning danger.
• It is safe to handle a lightning victim.
• Check for breathing and pulse–administer CPR and/or mouth-to-mouth resuscitation, if necessary.
• Check for other injuries: fractures, lightning entry and exit points (e.g., fingers, toes, belt buckles, jewelry).
• Do not move victims with suspected spinal injuries.
• Prevent patient from going into shock (cover with blanket, keep dry, do not let victim walk around).
• Take even stunned or otherwise unhurt victims to hospital for proper medical attention.
http://www.nws.noaa.gov/nwr
NOAA Weather Radio
Resources
NOAA/National Severe Storms Laboratoryhttp://www.nssl.noaa.gov/mag
NOAA/National Weather Servicehttp://www.lightningsafety.noaa.gov
Cloud Flash
White Lightning Symbols Are 4 Cloud-to-ground Flashes In Spider Flash on LDAR II - 17 August 2001 at 1515:38 UTC
Injury
START
END
Cloud-to-ground Lightning BeforeNearby Cloud-to-ground Strokes
Probability of Detection False Failure
Lead Time in Minutes Alarms to Warn
3 10
4 miles 58% 26% 43% 30%
6 miles 76% 60% 57% 17%
8 miles 85% 75% 63% 11%
10 miles 89% 81% 69% 9%
Warningradius
Time Lags Minutes Since Last Probability of Ground
Ground Stroke Stroke Within 2 Miles
0 100%
5 7%
10 4%
15 1%
20 0.8%
25 0.6%
30 0.5%
Responses to Lightning Injury
• Denial• Isolation• Self-medication by drugs and alcohol• Anger at family, professionals, others• Blame• Different person• Disappointment• Acceptance - Final stage
Dr. Mary Ann Cooper, April 1999