Thursday, November 7, 2013

The Landfall of Super Typhoon Haiyan

Thursday, November 7, 2013
8:17 p.m.

A visible satellite image of Super Typhoon Haiyan as it makes landfall Friday morning Philippine time. Credit: NOAA.

A few hours ago, Super Typhoon Haiyan, one of the strongest, and, pending further investigation, quite likely THE strongest tropical cyclone in recorded history not only at landfall but at peak strength at any moment in time, made landfall on the central coast of the Philippines. The Philippines are no stranger to powerful tropical cyclones and commonly receive 6-9 landfalls per year, but with 195 mph sustained winds at landfall and 235 mph gusts, a landfalling storm of this magnitude is unprecedented. The previous record for the windiest storm at landfall was Hurricane Camille, which made landfall near New Orleans in 1969 with sustained winds of 190 mph and a central pressure of 905 mb.

While there are currently no official pressure readings, NOAA estimated this morning (back on our side of the date line) that the central pressure of Haiyan was a staggering 858 mb. The previous lowest pressure ever officially recorded was 870 mb from Super Typhoon Tip in the Western Pacific in October 1979. Tip was also the largest tropical cyclone with a diameter of 1,380 miles. Haiyan is still extremely large, but it is much smaller than Tip: "only" 500 miles across (this still makes it one of the largest tropical cyclones ever recorded, though). However, a smaller storm means a more intense pressure gradient, and hurricane force winds extend out well over 50 miles from the center. Hurricane force winds are defined as sustained winds over 74 mph. Sea-Tac's all-time highest gust is 69 mph, and this was recorded just after 1 a.m. on December 15, 2006 as the most intense pressure gradient - the "bent-back occlusion" - of the famous/infamous Hanukkah Eve Storm swept through. Hurricane Wilma back in the historic Atlantic 2005 hurricane season had a central pressure of 882 mb. The bottom line is that if this estimate is verified, Haiyan will have absolutely shattered the record for the lowest pressure ever recorded at sea-level. Regardless, one thing's for sure... these pressure readings put our 970mb Hanukkah Eve peak reading to shame.

Infrared image of Haiyan further out at sea. Credit: NASA

This false color image gives a great idea of the structure of the storm. A common misconception is that extremely powerful typhoons have a symmetrical structure. This is only partly true. As you can see, the outer edges of the typhoon are not very symmetrical. This is due to rainbands, which are those long, elongated cloud bands you see on the periphery of the typhoon. As the distance to the eye decreases, the symmetry tends to increase. 

Take a look at the picture below. This is the same photo as the one at the top but is zoomed in. Notice how circular the eye is and how the shield of clouds is perfectly symmetrical around it.

Eye of the storm. Credit: NOAA

Pretty amazing, huh? Who knew that something so beautiful could cause so much destruction. I know you'll join me in praying for the very best for all those affected in one way or another by this storm.

Here's another infrared pic showing the symmetry of the strongest, inner parts of the storm. It's like a doughnut with a really small hole. That's my kind of doughnut.

Amazing symmetry. My tummy is growling. Credit: NOAA

Here's some radar imagery of Haiyan coming ashore. Look how freakishly heavy the rain directly to the south of the storm is! I can't even imagine what that, combined with 195 mph winds, would do to structures.

Radar image of Super Typhoon Haiyan a few hours after landfall, at 9:33 local time on November 8, 2013. Image via

Alright, stills are great, but let's take a look at some animated satellite pictures.

According to NOAA, Hurricane Katrina caused 81 billion dollars in damage (2005 USD). But the damage could have been much worse. Take a look at the animation below.

I got this one from The Weather Channel!

Katrina was only a Category 3 when it landed, with sustained winds at a mere 125 mph. A Category 3 is still a huge storm, but that's a far cry from the Category 5 it was when it was just a few hundred miles south. Meanwhile, Haiyan kept its strength all the way in. The animation below doesn't show it actually making landfall because this story is so new in development and I wasn't able to find one, but the satellite pictures above show that it didn't decrease in intensity for one second.

It keeps its strength all the way through. Credit: NOAA

As I finish up this post, the diameter has decreased to 400 miles and I'm sure the winds have decreased substantially as well. Tropical cyclones weaken very quickly when they are cut off from warm water and encounter terrain. I'll keep you posted on details as they come!


1 comment:

  1. Wow! Any idea how this affected the islands to the east in Micronesia, i.e. Pohnpei? It is hard to imagine how the people there would fare in such a huge storm.