Category Archives: Natural Disasters

Natural Disasters, June 23

1946    Vancouver Island Earthquake, struck Vancouver Island in British Columbia.

2001    An 8.4 Mw earthquake struck southern Peru with a maximum Mercalli Intensity of VIII, Severe. A destructive tsunami followed killing at least 74 people and injuring 2,687.

            Earthquakes are measured today using the Modified Mercalli Intensity scale. This scale measures the effects of an earthquake, rather than the moment magnitude. Mw would be the measure of the moment magnitude. The Mercalli scale is a revised version of the Rossi-Forel scale and has gone through a number of changes since first developed in 1884. Although there are twelve degrees defining the Modified Mercalli scale, we usually only see the most severe which are X, XI, and XII. The scale uses Roman Numerals and starts with I which is not felt except by a few. A good way to remember it is remember V, that is a moderate earthquake and is felt by nearly everyone around it. VI – VII are strong. VIII is severe and IX is violent, but the ones you usually see reported are X-XII, these are Extreme and are the ones with large amounts of destruction.

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Natural Disasters, June 22

1783    A poisonous cloud caused by the eruption of the Laki vocano in Iceland reached Le Havre in France.

1919    Fergus Falls Tornado, killing 57 people.

2002    An earthquake measuring 6.5 Mw stuck a region of northwestern Iran killing at least 261 people and injuring 1300 others eventually causing widespread public anger due to the slow official response.

2003    Aurora, Nebraska received the largest hailstone ever recorded, which measured approximately 7 inches (17.8 centimeters) in diameter and weighed approximately 1.5 pounds (680 grams). Another hailstone of that diameter measurement was recovered in Potter Nebraska on July 6, 1928.

Hail has a diameter of 5 millimeters which is a little less than ¼ inch. Hailstones measure between 5 mm and 15 cm. 15 cm is close to 6 inches in diameter. That is a big ball of ice if you get hit with one. The reason why some hailstones are bigger than others depends on the updrafts and how strong the storm is. Strong updrafts keep the hailstones aloft longer and they continue to build ice on their surface, and grow. The National Weather Service and Skywarn advises storm watchers to report hail over ½ inch. In the  United States, hail is usually between 1 inch and 1.75 inches or golf-ball sized. The NWS threshold for damaging hail is 1 inch or 2.5 cm.

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Natural Disasters, June 21

2002    An earthquake measuring 6.5 Mw struck a region of northwestern Iran killing 261 people causing widespread fear due to a slow official response.

2007    An  F5 tornado struck Elie, Manitoba in Canada destroying part of the town, but with no fatalities or injuries.

EF stands for Enhanced Fujita Scale. This is a method of rating the intensity of tornadoes based on the amount of damage they cause. There are six categories ranging from 0 to 5 with 5 being the most severe. An EF 5 tornado has wind speeds over 200 mph and total destruction of buildings.

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Natural Disasters, June 20

1959    A rare June hurricane struck Canada’s Gulf of St. Lawrence killing 35 people.

1990    Manjil-Rudbar Earthquake, 50,000 people are killed in northern Iran when an 7.4 Mw earthquake of maximum intensity X, which is extreme on the Maximum Mercalli Intensity scale struck.

I know I have mentioned this before, but a Mw is a megawatt. The watt is a unit of power and a mega watt is a million watts, or (106) watts. We often see this used to describe the power of an earthquake. To put it in perspective, a diesel locomotive is capable of putting out about 5 megawatts of power, a typical U.S. nuclear power plant produces a little more than 500 to 1000 megawatts of power during the summer months.

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Natural Disasters, June 19

1718 Gansu Earthquake, 73,000 people were killed, occurred on this day.

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Natural Disasters, June 18

I have no significant disasters on this day.

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Natural Disasters, June 17

1929    The town of Murchison, New Zealand is rocked by a 7.8 magnitude earthquake killing 17. At the time it was New Zealand’s worst natural disaster.

1946    Windsor tornado leaves 17 dead.

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