A Rare Easter Typhoon for the Philippines; Chile Flood Toll: 107 Dead or Missing

Typhoon Maysak will be a rare and unwelcome Easter visitor this weekend in the Philippines' Luzon Island. The people of the Philippines are used to seeing tropical cyclones, but not during Easter! Only seven tropical storms or typhoons have hit Luzon between January and April since 1945, an average of one such storm every ten years. At 2 pm EDT Friday the Joint Typhoon Warning Center (JTWC) put Maysak's top sustained winds at 90 mph, and the Japan Meteorological Agency (JMA) put Maysak's central pressure at 975 mb. Satellite loops on Friday afternoon showed the storm's heavy thunderstorms have shrunk greatly in areal coverage and intensity since the storm's Category 5 days, and an eye is no longer distinct. Maysak was under moderate wind shear of 10 - 20 knots, and there is some dry air surrounding the storm that will get driven into the core by the wind shear, further weakening the storm before landfall. The Joint Typhoon Warning Center (JTWC) is predicting that Maysak will be a Category 1 typhoon with 75 mph winds when it hits Luzon this weekend, and the main threat from the storm will be heavy rains causing flash floods. The 12 UTC Friday runs of the GFS and European models predicted that the center of Maysak would come ashore in Luzon near 20 UTC (4 pm EDT) Saturday. The 06 UTC Friday run of the GFDL model predicted that Maysak would bring a modest area of 4 - 8" of rain to northern Luzon, which is less than the typical tropical storm brings to the Philippines, and should not result in catastrophic flooding.


Figure 1. Tracks of all tropical storms and typhoons to affect the Philippines' Luzon Island between the months of January - April. Only seven such storms have hit Luzon since 1945, an average of one every ten years. Image credit: NOAA.

Maysak kills 9 in Micronesia
Maysak is responsible for widespread destruction and at least nine deaths in the Federated States of Micronesia. Estimates from The Red Cross suggested that there were at least 5,000 people who were in desperate need of food, water and shelter, and needed emergency assistance. Maysak passed through the Chuuk State of Micronesia over the weekend as a Category 1 typhoon, and Maysak's southern eyewall passed over the sparsely populated islands of Fais and Ulithi in the Yap State of Micronesia while the storm was at Category 5 strength. Most structures on Ulithi not made of concrete were damaged or destroyed by Maysak's powerful winds. The entirety of the island's crop were ruined by the typhoon's storm surge, with early estimates indicating that it would be a full year before crops could be planted again, due to salt water intrusion. Robert Speta has more details on the impacts on Ulithi on his Twitter feed.

Chile flood toll: 107 dead or missing
The death toll in Chile from severe flooding that hit March 23 - 26, 2015, is now 24, with 83 others officially listed as missing. According to EM-DAT, this would rank as Chile's 4th deadliest flood in recorded history. Although rainfall amounts were generally less than 2" (50.8 mm), the rains fell on Northern Chile's Atacama Desert region--the driest place on the planet. Antofagasta, which averaged just 3.8 mm of precipitation per year between 1970 - 2000, and has a long-term average of 1.7 mm of precipitation per year, received a deluge of 24.4 mm (0.96 inches) during the 24 hour period ending at 8 am EDT March 26. That's over fourteen years of rain in one day! According to weather records researcher Maximiliano Herrera, some areas in the Atacama Desert saw the equivalent of a century or so of rain in few hours. The 4 mm of rain that fell on the driest place on Earth--Quillagua, Chile--on March 23 - 25 was the first rain there in 23 years, and the amount that fell was about the same amount that had fallen in the previous fifty years. The rains triggered flooding that damaged some houses in the town. Apparently, the previous rain episode in Quillagua before 2015 was in 1918 or in 1919. All other precipition events were from blowing drizzle.

This is a chronicle of the biggest rainfall events in Antofagasta, Chile with daily amounts above 10 mm over the past century (from Maximiliano Herrera, who maintains a comprehensive set of extreme temperature records on his web site):

18 May 1912: 24 mm
3 July 1925:  16.3 mm
5 July 1927: 12.6 mm
13 July 1928:  13.3 mm
21 August 1930: 26.2mm/27.1mm (2 stations)
30 June 1932:  11.0 mm
13 June 1940:  39.4 mm/38.0 mm (2 stations)
27 July 1987:  22.8 mm
18-19 June 1991: 42.0 mm/17.0 mm (2 stations)

The 1912, 1940 and 1991 rain events all caused floods that had catastrophic consequences in terms of economical and human losses.


Video 1. Incredible flooding in ‪Chanaral, Chile‬, on March 25, 2015. I've seen flood videos of cars, trucks, and houses being washed downstream before, but railroad cars? Yikes! A better version of this video with sound is available on Facebook.


Video 2. Flash flooding in a town near the Chile/Peru border on March 25, 2015.

Chile's heavy rains were due to an unusually strong and persistent "cut-off" low pressure system that was trapped along the coast by an exceptionally strong ridge of high pressure, which also brought about another remarkable weather event--the warmest temperatures ever recorded in Antarctica (63.5°F). A cold front associated with the cut-off low hit the Andes Mountains, dumping rains over soils with very little vegetation (due to the dry climate.) Unusually warm ocean temperatures approximately 1°C (1.8°F) above average off of the coast meant that high amounts of water vapor were available to fuel the storm and generate exceptionally heavy rains. Heavy precipitation events are common in Chile during El Niño events, like we are experiencing now. El Niño brings warmer than average waters to the Pacific coast of South America where Chile lies.

This week’s WunderPoster: Aurora
Last month provided high-latitude
skywatchers with a spectacular example of the aurora, the phenomenon highlighted in this week’s WunderPoster. Commonly referred to as the “northern lights” (aurora borealis) or “southern lights” (aurora australis), these sky shows are a product of electrons spewed from the sun that interact with gases in Earth’s outermost atmosphere, anywhere from about 50 to 300 miles above the surface. Auroral activity is greatly enhanced when gigantic bursts of electromagnetic energy emerge from the sun’s surface during solar storms.


Figure 2. Katy Turk captured this amazing aurora from eastern Alaska last month. Image credit: wunderphotographer katy97780.

Have a great Easter weekend, everyone!

Jeff Masters and Bob Henson