Super Typhoon Koppu, known as Typhoon Lando in the Philippines, made landfall close to 1 a.m. local time on Sunday morning near the town of Casiguran in Luzon's Aurora Province, as a powerful Category 4 or 5 storm.
The storm was on the cusp of being declared a Category 5 monster from one of the official storm monitoring agencies in Japan and the U.S. before it crossed over land, officially with winds of 150 miles per hour, just shy of Category 5 strength.
Super Typhoon Koppu underwent a nightmarish period of rapid intensification that may have caught many of the 15 to 20 million residents of Luzon off guard.
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Just before people along the northeastern coast of Luzon in the Philippines -- from Cabantuan City to the small towns along the coast, including Casiguran and Dipaulao -- went to bed on Saturday evening, local time, Typhoon Koppu was a strong Category 2 storm.
It was powerful, worthy of respect, but not monstrously strong. The storm was not remotely near the scale of Super Typhoon Haiyan, for example, which struck well to the south of this area in 2013, leaving at least 7,300 dead or missing.
#LandoPH update from PAGASA as of 5am Follow weather alerts here: http://t.co/s5jjMPOJbC pic.twitter.com/EkveEP9dj1— Rappler (@rapplerdotcom) October 17, 2015
Fast forward about eight hours, to chaotic pre-dawn Sunday as Koppu made landfall as a ferocious Super Typhoon with winds of 150 miles per hour or higher. Such a storm is capable of wiping out entire towns from wind damage, and inflicting a grim toll along the coast from storm surge flooding.
The storm's rapid intensification was hinted at in weather forecasts from the Joint Typhoon Warning Center (JTWC) in the U.S. and the Japan Meteorological Authority, but JTWC forecasters had predicted it would peak at slightly lower intensity, with some forecasts showing the storm coming ashore as a Category 3 storm.
[img src="http://admin.mashable.com/wp-content/uploads/2015/10/Eyelandfall.jpg" caption="The eye of Super Typhoon Koppu, known as Typhoon Lando in the Philippines, making landfall early Sunday morning local time." credit="PAGASA" alt="Super Typhoon Koppu"]
As Super Typhoon Koppu shows, forecasting a storm's intensity fluctuations, even just six to 12 hours in advance, is still a tricky business, especially in the West Pacific, where routine hurricane hunter flights, which take place into storms in the Atlantic Ocean in order to obtain crucial real-time data on storm intensity and direction of movement, were discontinued years ago.
This is as bad as it gets. Life-threatening extreme winds over 260kph (160mph) moving ashore next few hrs. #LandoPH pic.twitter.com/JzLDoW9KAD— Anthony Sagliani (@anthonywx) October 17, 2015
Improved computer models have helped, but they don't ensure protection from nightmare scenarios such as this one, where people prepared for a Category 2, 3 or 4 storm, but got something far more vicious.
Typhoon Koppu is not just a problem for coastal communities. This storm's biggest threat is its rains, and it may inflict its greatest toll in northwestern Luzon.
Worst possible rainfall scenario
This storm is going to do something few storms of this strength do -- sit and spin over land, and then near land, for three to four full days, dumping almost unheard of rainfall totals in the process.
Acting weather bureau chief Esperanza Cayanan said another typhoon farther east and a high pressure area north of the country would hold Koppu in a "semi-stationary" position and shroud most of Luzon in rain for days.
Ferocious winds ripping through Maddela now #typhoon #LandoPH #Koppu #Philippines pic.twitter.com/FcM7iQ4lvW— James Reynolds (@EarthUncutTV) October 17, 2015
(function(d, s, id) { var js, fjs = d.getElementsByTagName(s)[0]; if (d.getElementById(id)) return; js = d.createElement(s); js.id = id; js.src = "//connect.facebook.net/en_US/sdk.js#xfbml=1&version=v2.3"; fjs.parentNode.insertBefore(js, fjs);}(document, 'script', 'facebook-jssdk'));ATM Storm category no. 3 #LandoPh at Palayan City.Posted by Zaldy Agustin on Saturday, October 17, 2015
"We are looking at the possible worst scenario, not to scare but to allow us to prepare," Cayanan said. "If it stays 24 hours ... and the downpour is sustained, we will surely have floods and landslides."
This may prove to be an understatement.
Some computer models are projecting that rainfall totals in northwestern Luzon will eclipse 50 inches, or 1,270 millimeters, by the time rain ends on Tuesday or Wednesday. If some projections are born out -- and there is little reason to doubt them considering that there is historical precedent for such deluges from such tropical weather systems in the Philippines -- rainfall totals could climb even higher, toward 60 to 80 inches, or about 1,500 to 2,000 millimeters or more.
As weather.com's Nick Wiltgen wrote, this would be the equivalent of receiving an entire year's worth of average precipitation in Miami, Florida, which is 61.92 inches, in just three or four days.
Such rains will cause potentially deadly flash flooding and mudslides as well as river flooding, and combined with the wind and storm surge damage, could lead to this storm being one of the most expensive natural disasters on record in a country that experiences the most natural disasters of any nation on Earth.
According to Wiltgen, the city of Baguio in northwestern Luzon received more than 2,200 millimeters of rain (87 inches) in four days from a tropical cyclone in 1911. In this area, the storm's westerly winds will run up and over a north-south mountain chain, helping to squeeze out moisture through a process called orographic enhancement.
"If Kuppo/Lando should stall or move along a path that keeps onshore winds blowing in the same direction for a long enough time," Wiltgen wrote, "highly localized rainfall amounts topping 2,000 millimeters (nearly 80 inches) would not be unrealistic."
To prepare for the flooding, local officials have been conducting forced evacuations of communities historically affected by flash flooding and landslides. Authorities also evacuated coastal villages that risked getting hit by storm surge flooding.
President Benigno Aquino III appeared Friday on national television to warn Filipinos about the typhoon and appealed for cooperation to prevent casualties.
It was the first time Aquino had personally issued a storm warning on television since super Typhoon Haiyan barreled through the central Philippines in November 2013.
Metropolitan Manila, the sprawling Philippine capital of 12 million, about 145 kilometers (91 miles) southwest of Aurora, will be spared from the brunt of the typhoon, but will see heavy rain, forecaster Adzar Aurelio said.
Additional reporting by the Associated Press.