By:
Jeff Masters and Bob Henson
, 2:13PM,GMT on March 16,2015
Figure 1. Samuel, only his first name given, kicks a ball through the ruins of their family home as his father, Phillip, at back, picks through the debris in Port Vila, Vanuatu in the aftermath of Cyclone Pam Monday, March 16, 2015. Pam destroyed or damaged 90 percent of the buildings in the capital. Other portions of Vanuatu received much stronger winds. (AP Photo/Dave Hunt, Pool)
Pam was at its peak strength, with 165-mph Category 5 winds, when it passed over several small Vanuatu Islands to the north of Efate Island, Vanuatu's most populous island (population 66,000.) Pam is one of only two Category 5 cyclones in recorded history to make landfall on a populated island in the waters east of Australia. The only other Category 5 landfall event among the nine other Category 5 storms to affect these waters since 1970 was by the strongest tropical cyclone on record in the basin, Cyclone Zoe of 2002. Zoe made a direct hit as a Category 5 storm on several small islands in the Temotu Province of the Solomon Islands with a total population of 1700. There was one other close call: the eye of Category 5 Tropical Cyclone Percy passed 15 miles east of Ta'u, American Samoa, on February 16, 2005, but caused minimal damage.
Pam's weaker southwest quadrant eyewall hit Efate on Friday the 13th, bringing terrible damage there. Continuing to the south, Pam hit the southern islands of Erromango (population 2,000) and Tanna (population 29,000), Even though Pam had weakened slightly to 155 mph winds by this time, these islands took a catastrophic pounding, since they were hit by the stronger southeastern portion of the eyewall, where the clockwise spin of the storm aligned with its southerly forward motion to create the strongest winds.
Figure 2. Tropical Cyclone Pam as seen on March 13, 2015, as its southeast eyewall battered the Vanuatu island of Tanna. At the time, Pam was a high-end Category 4 storm with 155 mph winds. Tanna (population 29,000) probably took the worst punishment from the storm, due to the fact it was hit by the stronger southeast eyewall, where the clockwise spin of the storm aligned with its southerly forward motion. At least five people are confirmed dead on the island. Thanks go to wunderground member barbamz for saving this image.
Cyclone Olwyn: a costly event for Western Australia
Though much weaker than Pam, Severe Tropical Cyclone Olwyn made its presence known on Friday as it raked a lengthy portion of Australia’s western coast, with peak winds of 100 mph near landfall. Olwyn’s path--paralleling the coast and gradually inland, with the strongest winds on the landward side--is roughly analogous to a hurricane moving slowly north-northeast up the west coast of Florida.
Figure 3. Track of Cyclone Olwyn. Image credit: Wundermap.
Olwyn produced winds of 70 mph, gusting to 87 mph, in the town of Carnarvon (thanks to Weather Channel senior meteorologist Matt Crowther for this report). The region’s banana crop, part of an agricultural system that produces roughly $70 million US in value each year, was reportedly wiped out, and more than 1,000 residents were still without power on Monday. Olwyn accomplished the rare feat of passing almost directly over a profiler (an upward-pointing, wind-measuring radar) located at Carnarvon’s airport. The profiler detected 115-mph winds at about 3000 feet above ground, according to Sarah Fitton (Australia Bureau of Meteorology).
Record-melting heat across western U.S.
From California to North Dakota, a large part of the nation’s northwest half experienced summer-like heat over the weekend. Some of the more ominous reports came from fast-drying California, where the rainy season is limping to a halfhearted end. Many stations around Los Angeles and San Diego set record highs near or above 90°F on each day Friday through Sunday. In the San Francisco Bay area, all-time monthly heat records were notched on Saturday at Salinas Airport (92°F), San José (89°F), Monterey (87°F), and on Sunday in Fresno (91°F). The heat pushed into the northern Rockies and northern Great Plains on Sunday, with the all-time March record falling at Rapid City, SD (84°F). Many other locations saw their warmest day for so early in the season. In North Dakota, both Fargo (75°F; normal high 35°F) and Grand Forks (70°F; normal high 33°F) had their earliest 70°F readings on record--though by just one day, as the Great Warm Wave of March 2012 headed toward its amazing apex starting on March 16. More records appear certain to fall over the central Great Plains on Monday, with even the impressive numbers from 2012 in jeopardy at some locations.
At last: a seasonal snow record for Boston
The snowy onslaught that gripped Boston in late January and February smashed records for the most snow observed there in any single month (64.8”, besting the 43.3” from January 2005). After a reprieve in early March, a quick shot of snow on Sunday afternoon secured this winter’s place in city history as the snowiest on record. Sunday’s 2.9” pushed the seasonal total to 108.6”, breaking the record of 107.6” set in 1995–96. In a Sunday article, the Weather Channel’s Jon Erdman highlighted these and many other noteworthy aspects of Boston’s snow siege of 2014–15. The city’s snow records date back to 1891–92.
What about the 250-plus years between the arrival of the Puritans and the launch of modern snow-data collection in Boston in 1891? According to Weather Underground historian Christopher Burt, very few sites across New England maintained regular monthly and seasonal snowfall data prior to 1891. According to Burt: ”Cotton Mather noted that 36” - 42” of snow on level buried Boston between February 27 and March 9, 1717, as related in one of the first publications of the Massachusetts Historical Society. But there is no record of how much snow may have accumulated in the city over the course of that season. The same goes for all the winter seasons in Boston until we have the modern record. Bottom line: although we don’t know how much snow may have fallen each season prior to 1891-82, there is no positive or even anecdotal historical evidence to indicate that this season is not likely the snowiest on record since the founding of the city and, of course, in the modern record.”
Figure 4. Boston’s Beacon Hill on February 15, during the city’s record-setting streak of January/February snowstorms. Image credit: wunderphotographer Orfeo.
Our next post will be on Wednesday at noon at the latest.
Bob Henson and Jeff Masters
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