User:Runningonbrains/Enhanced Fujita Scale

The Enhanced Fujita Scale, or EF Scale, is the scale for rating the strength of tornadoes in the United States. Implemented in place of the now-obselete Fujita scale, it was used starting February 1, 2007. The scale has the same basic design as the original Fujita scale, with 6 categories representing increasing degrees of damage. It was revised to reflect better examinations of tornado damage surveys, so as to align wind speeds more closely with associated storm damage. The new scale was publicly unveiled at a conference by the American Meteorological Society in Atlanta on February 2, 2006.

Parameters
The six categories for the EF Scale are listed below, in order of increasing intensity.

Differences from the Fujita scale
The new scale takes into account how most structures are designed. The wind speeds on the original scale were deemed by meteorologists as being too large and engineering studies have shown that slower winds can cause the same damage as that of winds of 300 mph. The new scale lists an EF-5 as a tornado with winds at or above 200 mph (324 km/h), thought to be a much more accurate representation of the surface wind speeds in the most violent tornadoes. None of the tornadoes recorded on or before January 31, 2007 will be re-categorized.

Essentially, there is no functional difference in how tornadoes are rated. The old ratings and new ratings are cleanly connected with a linear formula. The only differences are adjusted wind speeds, measurements of which weren't used in previous ratings, and refined damage descriptors, to make it easier to rate tornadoes which strike few structures. Twenty-eight Damage Indicators (DI), with descriptions such as "Double-wide mobile home" or "Strip mall". with Degrees of Damage (DOD) to determine wind estimates. Different structures, depending on their building materials and ability to survive high winds, will have their own DIs and DODs.

Since the new system will still use actual tornado damage to estimate the storm's wind speed, the National Weather Service states that the new scale will likely not lead to an increase in a number of tornadoes classified as EF5 (the lower wind speed ranges have been adjusted as better estimates of what is needed to incur the damage). The upper bound of the wind speed range for EF5 is open — in other words, there is no maximum wind speed designated.