Several years ago, I published an article with DRJ entitled “Facts and Stats” that listed the scales of measurement for various types of phenomena, mostly weather related. Recently, I was amazed to see a few of these have since been updated ...
Cyclones, Hurricanes, and Typhoons
Hurricane season in the Atlantic begins June 1st and ends November 30th. The Eastern Pacific hurricane season begins May 15th and also ends November 30th.
Cyclone – An atmospheric closed circulation rotating counter-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.
Hurricane/typhoon – A tropical cyclone in which the maximum sustained surface wind (using the U.S. one-minute average) is 64 kt (74 mph or 119 km/hr) or more. The term hurricane is used for Northern Hemisphere tropical cyclones east of the International Dateline to the Greenwich Meridian. The term typhoon is used for Pacific tropical cyclones north of the Equator west of the International Dateline.
- Tropical Depression: A tropical cyclone with maximum sustained winds of 38 mph (33 knots) or less.
- Tropical Storm: A tropical cyclone with maximum sustained winds of 39 to 73 mph (34 to 63 knots).
- Hurricane: A tropical cyclone with maximum sustained winds of 74 mph (64 knots) or higher. In the western North Pacific, hurricanes are called typhoons; similar storms in the Indian Ocean and South Pacific Ocean are called cyclones.
- Major Hurricane: A tropical cyclone with maximum sustained winds of 111 mph (96 knots) or higher, corresponding to a Category 3, 4 or 5 on the Saffir-Simpson Hurricane Wind Scale.
Saffir-Simpson Hurricane Wind Scale – The Saffir-Simpson Hurricane Wind Scale is a 1 to 5 rating based on a hurricane’s sustained wind speed. This scale estimates potential property damage. Hurricanes reaching Category 3 and higher are considered major hurricanes because of their potential for significant loss of life and damage. Category 1 and 2 storms are still dangerous, however, and require preventative measures. In the western North Pacific, the term “super typhoon” is used for tropical cyclones with sustained winds exceeding 150 mph. The following table shows the scale broken down by winds:
| Category | Wind Speed (mph) | Damage |
| 1 | 74 - 95 | Very dangerous winds will produce some damage |
| 2 | 96 - 110 | Extremely dangerous winds will cause extensive damage |
| 3 | 111 - 129 | Devastating damage will occur |
| 4 | 130 - 156 | Catastrophic damage will occur |
| 5 | > 157 | Catastrophic damage will occur |
| 5 | > 157 | Catastrophic damage will occur |
Source: http://www.nhc.noaa.gov/
Earthquakes Richter Magnitude Scale:
| Magnitude | Earthquake |
| 4 | Minor |
| 5 | Moderate |
| 6 | Strong |
| 7 | Major |
| 8 | Great |
Note: Earthquake magnitude is generally measured using the Richter Magnitude Scale while intensity is measured using the Modified Mercalli Intensity Scale. In recent years, seismologists have developed a new scale, called Moment Magnitude to describe the size of an earthquake.
Source: http://pubs.usgs.gov/ and http://earthquake.usgs.gov/
Hail
| Hail size and diameter in relation to TORRO Hailstorm Intensity Scale. | ||
| Size code | Maximum Diameter mm | Description |
| 0 | 5-9 | Pea |
| 1 | 10-15 | Mothball |
| 2 | 16-20 | Marble, grape |
| 3 | 21-30 | Walnut |
| 4 | 31-40 | Pigeon's egg > squash ball |
| 5 | 41-50 | Golf ball > Pullet's egg |
| 6 | 51-60 | Hen's egg |
| 7 | 61-75 | Tennis ball > cricket ball |
| 8 | 76-90 | Large orange > Soft ball |
| 9 | 91-100 | Grapefruit |
| 10 | >100 | Melon |
Source: http://www.torro.org.uk/
Tornadoes
Enhanced Fujita Scale:
| OPERATIONAL EF SCALE | |
| EF Number | 3 Second Gust (mph) |
| 0 | 65-85 |
| 1 | 86-110 |
| 2 | 111-135 |
| 3 | 136-165 |
| 4 | 166-200 |
| 5 | Over 200 |
On 1 February 2007, the Enhanced Fujita (EF) scale replaced the original Fujita scale in all tornado damage surveys in the United States. It is important to note that, despite the improvements, the EF-scale still remains a set of wind estimates based on 8 levels of damage to 28 different types of structures and vegetation.
A Family Preparedness Kit Should Include:
- A three-day supply of water (one gallon per person per day) and food that won’t spoil
- one change of clothing and footwear per person
- one blanket or sleeping bag per person
- a first-aid kit, including prescription medicines
- emergency tools, including a battery-powered NOAA Weather Radio and a portable radio, flashlight, and plenty of extra batteries
- an extra set of car keys and a credit card or cash
- special items for infant, elderly, or disabled family members.
Source: http://www.nws.noaa.gov/
Disclaimer: The views and opinions expressed in this column are those of the author and do not necessarily reflect the official policy or position of KPMG LLP.
Robbie Atabaigi, MBCI, MBCP, CISA, is a member of KPMG LLP’s Southeast Information Protection and Business Resiliency practice in Atlanta. She has more than 29 years of experience in developing and evaluating many aspects of enterprise risk management including emergency preparedness and response, crisis management, disaster recovery, and business continuity for prominent international companies. Atabaigi is a member of the DRJ Editorial Advisory Board and is a member of the Community Emergency Response Team in Cobb County, Georgia.
