The Old Farmer's Almanac 2015 (37 page)

How to Measure Wind Speed

The
Beaufort Wind Force Scale
is a common way of estimating wind speed. It was developed in 1805 by Admiral Sir Francis Beaufort of the British Navy to measure wind at sea. We can also use it to measure wind on land.

Admiral Beaufort arranged the numbers 0 to 12 to indicate the strength of the wind from calm, force 0, to hurricane, force 12. Here’s a scale adapted to land.

“Used Mostly at Sea but of Help to All Who Are Interested in the Weather”

Retired Atlantic Hurricane Names

These storms have been some of the most destructive and costly.

How to Measure Hurricane Strength

The
Saffir-Simpson Hurricane Wind Scale
assigns a rating from 1 to 5 based on a hurricane’s intensity. It is used to give an estimate of the potential property damage from a hurricane landfall. Wind speed is the determining factor in the scale, as storm surge values are highly dependent on the slope of the continental shelf in the landfall region. Wind speeds are measured at a height of 33 feet (10 meters) using a 1-minute average.

Category One.
Average wind: 74-95 mph. Significant damage to mobile homes. Some damage to roofing and siding of well-built frame homes. Large tree branches snap and shallow-rooted trees may topple. Power outages may last a few to several days.

Category two.
Average wind: 96-110 mph. Mobile homes may be destroyed. Major roof and siding damage to frame homes. Many shallow-rooted trees snap or topple, blocking roads. Widespread power outages could last from several days to weeks. Potable water may be scarce.

Category three.
Average wind: 111–129 mph. Most mobile homes destroyed. Frame homes may sustain major roof damage. Many trees snap or topple, blocking numerous roads. Electricity and water may be unavailable for several days to weeks.

Category four.
Average wind: 130–156 mph. Mobile homes destroyed. Frame homes severely damaged or destroyed. Windborne debris may penetrate protected windows. Most trees snap or topple. Residential areas isolated by fallen trees and power poles. Most of the area uninhabitable for weeks to months.

Category five.
Average wind: 157+ mph. Most homes destroyed. Nearly all windows blown out of high-rises. Most of the area uninhabitable for weeks to months.

How to Measure a Tornado

The original
Fujita Scale
(or F Scale) was developed by Dr. Theodore Fujita to classify tornadoes based on wind damage. All tornadoes, and other severe local windstorms, were assigned a number according to the most intense damage caused by the storm. An enhanced F (EF) scale was implemented in the United States on February 1, 2007. The EF scale uses 3-second gust estimates based on a more detailed system for assessing damage, taking into account different building materials.

Wind/Barometer Table

Windchill Table

As wind speed increases, your body loses heat more rapidly, making the air feel colder than it really is. The combination of cold temperature and high wind can create a cooling effect so severe that exposed flesh can freeze.

Example:
When the temperature is 15°F and the wind speed is 30 miles per hour, the windchill, or how cold it feels, is −5°F. For a Celsius version of this table, visit
Almanac.com/WindchillCelsius
.

–
courtesy National Weather Service

In the Garden

HERBS TO PLANT IN LAWNS

Choose plants that suit your soil and your climate. All of these can withstand mowing and considerable foot traffic.

Ajuga or bugleweed
(Ajuga reptans)

Corsican mint
(Mentha requienii)

Dwarf cinquefoil
(Potentilla tabernaemontani)

English pennyroyal
(Mentha pulegium)

Green Irish moss
(Sagina subulata)

Pearly everlasting
(Anaphalis margaritacea)

Roman chamomile
(Chamaemelum nobile)

Rupturewort
(Herniaria glabra)

Speedwell
(Veronica officinalis)

Stonecrop
(Sedum ternatum)

Sweet violets
(Viola odorata
or
V. tricolor)

Thyme
(Thymus serpyllum)

White clover
(Trifolium repens)

Wild strawberries
(Fragaria virginiana)

Wintergreen or partridgeberry
(Mitchella repens)

LAWN-GROWING TIPS

• Test your soil: The pH balance should be 7.0 or more; 6.2 to 6.7 puts your lawn at risk for fungal diseases. If the pH is too low, correct it with liming, best done in the fall.
  
• The best time to apply fertilizer is just before it rains.
  
• If you put lime and fertilizer on your lawn, spread half of it as you walk north to south, the other half as you walk east to west to cut down on missed areas.
  
• Any feeding of lawns in the fall should be done with a low-nitrogen, slow-acting fertilizer.
  
• In areas of your lawn where tree roots compete with the grass, apply some extra fertilizer to benefit both.
  
• Moss and sorrel in lawns usually means poor soil, poor aeration or drainage, or excessive acidity.
  
• Control weeds by promoting healthy lawn growth with natural fertilizers in spring and early fall.
  
• Raise the level of your lawn-mower blades during the hot summer days. Taller grass resists drought better than short.
  
• You can reduce mowing time by redesigning your lawn, reducing sharp corners and adding sweeping curves. During a drought, let the grass grow longer between mowings and reduce fertilizer.
  
• Water your lawn early in the morning or in the evening.