Gusts caused by a lot of turbulence in storm systems with a lot of energy are extreme or high wind. It includes ex-tropical cyclones or mid-latitude storms.
Bands of generally strong winds are associated with areas of large pressure gradients in these systems. These bands are frequently near the low-pressure centre.
Due to a landfalling storm, an extreme(high) wind warning is issued by the National Weather Service for locations. The speed receive of winds of 100 knots (185 km/h) or greater within one hour.
When high(extreme) winds pose a major threat of casualties, extreme wind warnings are issued at the county or sub-county level to provide guidance to the general public. Their issuance is meant to cover as small an area as possible, and they can only be issued two hours prior to the commencement of high winds.
Hurricanes Charley and Jeanne slammed Florida in 2004 and sparked the idea for a short-fused warning system for high winds. Strong winds prompted the National Weather Service weather forecast office in Melbourne, Florida to issue a special bulletin advising immediate action due to the onset of life-threatening winds by embedding the bulletin within a tornado warning, giving the bulletin greater visibility and urgency during Charley’s passage across the state.
Later same year, as the powerful winds of Hurricane Jeanne swept onshore from the east, the forecast office issued similar “tornado” warnings. Emergency management officials praised the unconventional use of tornado warnings for strong hurricane winds, calling it an amazing means of saving lives.
The Melbourne forecast office presented guests at the annual NOAA Hurricane Conference in December 2004 on their use of the special tornado warning, lobbying for and eventually obtaining consensus on a specialised official National Weather Service product for high winds.Extreme Wind Speeds.
Extreme(High) Wind Analysis
Extreme value analysis deals with statistical inference on extreme values and has applications in a variety of domains. Environmental extremes (such as river flow, wind) and engineering are two of the key areas of concentration.
Types of Extreme(High) Value Data
In practise, there are two main models for extracting extreme(High) wind data from a sequence of wind measurements.
These two methods are:
- Epochal method
- Peak over threshold method
We will have a complete description on these two.
We use the epochal method to get the highest extreme value for a certain time period. If we collect wind speeds on a daily basis, for example, we may choose the most extreme value for each month.
So, if we had 60 months of data, the 60 monthly maximum wind speeds would be our extreme value series. It’s worth noting that these aren’t always the 60 most extreme points in the daily data.
Even if a month has multiple high wind speed events, it will only return a single value. Similarly, a month with relatively low wind speeds would nevertheless provide a single highest result.
Peak over threshold method
The peaks over threshold approach, on the other hand, uses a single threshold value. Then we include any values above that level in our extreme value series. Any daily wind speeds over the set threshold will be included in the extreme value series in our example of daily wind speeds gathered over 60 months.
The number of extreme values will not be fixed, unlike the epochal method. In our hypothetical scenario, we could have months with no extreme values and others with several extreme values. The number of extreme values will be determined by the threshold selected.
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High Wind Safety Rules
The safest place to during high winds is indoors
Postpone outdoor activities when wind advisory or high wind warning has been issued.
If you are caught outside during high winds:
- Take refuge close to a structure or in a shelter.
- Keep a safe distance from roads and railroad lines, as a blast of wind could throw you into the path of an oncoming car.
- On outdoor pathways, use railings if they are present, and avoid other elevated areas without suitable railing, such as roofs.
- Keep an eye out for flying debris.
- During heavy wind gusts, tree limbs may break and roadway signs may fall loose.
- Keep an eye out for falling things from nearby balconies.
In the event of a downed power line:
- Make a request for assistance. Downed lines should be reported to your local utility emergency centre as well as the police. Do not attempt to clear lines or remove debris on your own.
- Anything that could come into contact with downed lines, like as automobiles or tree limbs, should be avoided. In some situations, puddles and even wet or snow-covered ground can conduct electricity. Others should be warned to keep away.
- Do not touch somebody who has been shocked and may have come into direct or indirect contact with a power line. It’s possible that you’ll become a second victim. By calling a rescue service, you can get medical help as soon as feasible.
- Stay inside your vehicle if a line falls on it. Take care not to touch any of your vehicle’s metal frame. Honk your horn, roll down your window, and warn anyone who comes close that there is a hazard. Request that a police officer be dispatched. Unless the automobile catches fire, do not get out until aid arrives. To leave, open the door but don’t take a step outside. Jump to safe ground without contacting any of the metal parts of the car’s exterior and flee as swiftly as possible.
If you are driving:
- Slow down and keep both hands on the wheel.
- Keep an eye out for anything that may blow over the road and into your path.
- Keep a safe space between you and automobiles in adjacent lanes, since severe gusts can knock a car out of its lane.
- When driving a high-profile vehicle, such as a truck, van, or SUV, or towing a trailer, take particular precautions because vehicles are more likely to be pushed or even flipped by heavy wind gusts.
- If the winds are strong enough to make driving unsafe, pull over to the side of the road and pull over, ensuring sure you’re clear of trees or other tall items that could fall onto your car. Keep driving and turn on the danger lights until the wind dies down.
Finally, we reach at the point that extreme wind warning will be the alert issued by National Weather Service for areas that will receive a sustained wind knot greater than 185Km/h.