Freakish Sleet, Snow, and Cold Sting Southeast Asia

By: Bob Henson , 5:21PM,GMT on January 26,2016




 

At least 87 deaths have been reported from a cold wave over the last week that’s brought dangerously chilly temperatures and wintry precipitation to tropical and subtropical latitudes of Southeast Asia, as well as brutally frigid readings further north. The culprit is a southward extension of the upper-air circulation that rings the Arctic (a.k.a. the “polar vortex”), which allowed an unusually strong Siberian surface high to build southeastward (see Figure 1). In the northern part of Inner Mongolia, an autonomous region of China, the city of Genhe came close to its all-time low of –49.6°C on Thursday, January 21, when it dipped to –47.8°C (–54.0°F). At least 24 locations in China reportedly hit all-time lows between Friday and Sunday.

The greatest risk for casualties from this cold wave is at lower latitudes, where warm clothing and home heating are less common and people are less adapted to sudden chill. The 85 deaths above were reported from Taiwan, where many victims were found inside unheated structures. By Tuesday, readings in Taipei had not cracked 10°C (50°F) for a full three days, with nights dipping as low as 4°C (39°F). Two other cold-related deaths have been reported in Thailand, and that number could rise sharply.


Figure 1. An intense surface high boasted a central pressure of at least 1066 millibars at 0700Z Saturday, Jan. 23, 2016. The frigid high sent cold air cascading across the continent to the lowlands of Southeast Asia. Image credit: Thai Meteorological Department, courtesy Christopher Burt.

Snow on the South China coast
Snow is virtually unheard of across Southeast Asia, even at elevation, so the last several days have given millions of people their first-ever glimpse of the white stuff. On Sunday, the city of Ghangzhou, China (metro population 23 million) saw its first snowfall since at least 1949, when the People’s Republic of China was established. “Most [residents] had never before experienced snow,” reported the Hong Kong Standard. “People living on Beijing Road in Yuexiu ran excitedly from their homes to take pictures. Children opened their mouths to catch snowflakes.” According to weather records researcher Maximiliano Herrera, this may have been Guangzhou’s first snow since 1893, when six inches fell.

Just across Kowloon Bay, temperatures in Hong Kong plummeted to 3.1°C (37.6°F) on Sunday, the coldest reading observed there since 1957. Schools were closed on Monday due to the intense chill, and social media outlets were filled with reports of snowflakes, although the Hong Kong Observatory reported that the event actually consisted of “rain with small ice pellets.” About 40 miles to the west, the island of Macau--the world’s most densely populated urban area--reported its first occurrence of snow since 1893, according to Herrera. At Macau International Airport, WU’s daily weather summary for Sunday shows several hours of ice pellets.

The big chill in Thailand
WU climate historian Christopher Burt gave us an update from northern Thailand’s largest city, Chiang Mai, located at latitude 18.8°N and an elevation of 1020 feet. The average high and low for January 26 in Chiang Mai are 87°F and 60°F. “It is the daytime cold temperatures here that are probably unprecedented, not the daily low temps,” he told me. “We went from a monthly record high of 36°C [96.8°F] on Saturday to 90°F at noon on Sunday to 55°F with rain at noon on Monday, an amazing drop in 24 hours for this neck of the woods. Today [Tuesday] it was 52°F and drizzling at noon. Our high for the day was 54°F, the coldest daily max in memory for the area. It seems virtually certain that snow must have been falling in the mountains of northern Thailand above the 1500-1800 m level [around 5000-6000 feet].” Herrera noted: “On Tuesday the max temperature was higher at Tafjord, Norway, than in Chiang Mai, Thailand…in January!”

Snow has never been confirmed to fall in Thailand, even in historical records dating back to the 1600s, according to Burt and Herrera (although hailstorms do occur). Likewise, the mountains of Laos have never officially reported snow cover. Brief flurries were reported in Laos on Tuesday down to elevations below 1000 meters (3300 feet), according to Herrera. Both Thailand and Laos might have received accumulating snow at high elevation on Tuesday--although if the snowfall were brief and limited to sparsely populated areas, it might have gone undocumented even if it did occur. Temperatures across Southeast Asia should be rising dramatically over the next couple of days, as the air mass aloft is already warming.


Figure 2. Visitors check out snowfall at Yangmungshan National Park near Taipei, Taiwan, on Monday, January 25, 2016. Image credit: Billy H.C. Kwok/Getty Images.

Further north, in mountainous Taiwan, measurable snow fell at altitudes as low as 500 meters (1600 feet), prompting many residents to head for the hills for a rare peek at a fleeting winter wonderland. Just outside Taipei, the higher elevations of Yangmingshan National Park reported 5 cm (about 2”). Snowfall was also widespread in Japan, with even the far-southern island of Amami-Oshima reporting its first flakes in 115 years. An all-time record low of 5.2°C (41.4°F) was reported on Sunday at Kume Island, Okinawa, where “sleet” was recorded for the first time in 39 years. (Note that in the United Kingdom and many other countries, the term “sleet” refers to rain mixed with snow.)

Several other countries in the region have been affected by record cold and historic snowfall, according to Herrera, one of the world's top climatologists, who maintains a comprehensive list of extreme temperature records for every nation in the world on his website. We’ll provide an update on this historic event in a subsequent post.

Bob Henson