The dangerous intensification of Hurricane Willa, explained

After a mbadive intensification this weekend, Hurricane Willa swirls to the west coast of Mexico as a Category 4 storm. All that concerns the storm will be life threatening, warns the National Hurricane Center: Winds Hurricane force, flash floods, landslides and storm surges are expected in its path. "Preparations to protect life and property must be done in a hurry," says the National Hurricane Center.

A few days ago, Hurricane Willa was a tropical storm, CNN reports. On Monday morning, Willa became a Category 5 hurricane with winds reaching speeds of 165 km / h. On Monday afternoon, winds were slowed to 150 miles by the hour and the National Hurricane Center brought the storm back to a category 4. The storm is expected to hit the Isla Archipelago. Marías off the west coast of Mexico Tuesday morning before hitting the west-central Mexico metropolitan later in the day.

While the storm should continue to lose strength, the National Hurricane Center predicts it will probably not lose much steam before reaching Mexico. "Unfortunately, the landing is tomorrow, so he does not have much time to weaken," says Phil Klotzbach, atmospheric scientist at Colorado State University. The storm should still be a major hurricane when it hits land. "It really looks like a serious threat," he says.

After the hurricanes that hit the east coast of the United States, a hurricane on the Pacific coast of North America may seem surprising. But in fact, the northeast Pacific is actually more Klotzbach says cyclones are more hurricane than the Atlantic. So far, three Category 5 storms have formed in the northeast Pacific this year, likely due to a combination of favorable weather conditions and warm ocean waters. And given the frequency, duration and intensity of storms, it's the most active hurricane season in the region, he says.

The edge spoke with Klotzbach about hurricanes in the Pacific, Willa's rapid intensification and why this year is so strange.

This interview has been modified for clarity and brevity.

Is Hurricane Willa unusual?

This is unusual in that it escalates rapidly. Models have always been very aggressive in developing this storm. the [National] Hurricane Center has been monitoring this phenomenon for a while and has not really done much. The bottom fell and a tropical depression went from tropical depression to category 5 in 48 hours, which is very impressive. Not the fastest, but certainly up there in terms of rapid intensification.

As far as its trajectory is concerned, it is rather typical of end-of-season storms in the eastern Pacific. They tend to move west, then north and back to Mexico. So for the west coast of Mexico, buying items from October to November is not so rare. I think it will probably weaken. But even if it's a four or three, it's certainly one of the strongest storms that hit them.

Is there a pattern of hurricane training in the Pacific and does Hurricane Willa fit this pattern?

In the Pacific, the water temperature gets colder as you head north – that's why we do not see hurricanes hit California – and the shear gets worse. Storms in the northeast Pacific are therefore formed in a small, narrow latitude-longitude region. And then most of them go to the west and head north, reach cold waters and die. Most hurricanes in the northeastern Pacific have no impact on people. This is why, in research, it is probably the most neglected hurricane basin.

But then you obviously get those storms, as we had Patricia [in 2015], which is probably the one that people remember most. Hurricane Kenna in 2002 was a very violent hurricane that hit western Mexico and killed four people when it made landfall. Certainly, there are those kinds of storms that make these right turns turn in Mexico, and Kenna is actually quite a good badog in terms of trajectory because it has landed in every way. [Category] 4 October 25th – so at about the same time. These types of mighty hurricanes have already hit western Mexico, but it's obvious that this one has the potential to be powerful enough when it strikes.

We do not hear about hurricanes in the Pacific as often as hurricanes in the Atlantic, is it because there are fewer?

There is actually more! The hurricane season in the northeast Pacific has been the most active ever recorded, and no one pays attention to storms because they usually fall in the middle of nowhere and die. So, unless they reach Hawaii, like Lane, people ignore them and say, "It's a beautiful hurricane in the middle of nowhere that has no impact on anyone." But the northeast Pacific has been extremely active. season. Climatologically, the Atlantic has about 12 storms and the Northeast Pacific has 16, so they receive more. Not every year, but in general it's more active than the Atlantic.

Why is that?

Simply because the shear is weaker. The shear is basically the change of direction of the wind with the height in the atmosphere. The idea is therefore that hurricanes want to be standing up. If you suffer from shear – if you have winds blowing in one direction, say, coming from the east, and winds in the other direction coming from the west – the hurricane's circulation will suffer. This disrupts the vortex and you can not get the deep thunderstorms you need to withstand the storm. Shear is therefore detrimental to hurricanes and, when you feel a lot, it tends to really break the season.

So you have a low shear zone off the coast of Mexico and the waters are certainly very hot to deal with cyclones. One of the ideas is that many of the storms that are forming in the northeastern Pacific come from disturbances caused by Africa. If they do not grow in the Atlantic, they sometimes go [go all the way across the caribbean and] develop in the eastern Pacific. So, in many ways, the Atlantic and the Northeast Pacific tend to be inversely related: when the Atlantic is very active, the Northeast Pacific tends to be calm and vice versa .

Is this happening this year?

This year is a strange year. This year is a little above normal in the Atlantic. But normally, when the northeast Pacific is as active as it is this year, the Atlantic is not expected to be very active, so it's a little unusual in that regard. This is one of the many things we are trying to understand for this year: how the relationships we have in our head do not always work.

Why did Willa intensify so quickly?

The waters are hot. I've looked for Willa, they have a higher degree of heat than normal. What is interesting is that theoretical research indicates that when the temperature of your water reaches a certain level, the hurricane can only become very intense.

So, Willa is close to the strength of a storm with the current temperature of the water. Which basically means that the environment has to be pretty much perfect – because normally hurricanes are nowhere near as strong as possible for the water temperature because of shear and other factors that come into play and damage the storm. The problem with Willa is that in theory, he really can not be stronger than he is, given the temperature of the water under which he is. And it seems that the shear will increase. So, even if the water temperature gets a little warmer, the shear will increase, and that should darken the storm a bit before it hits the coast.

What is the role of climate change here in the Pacific hurricane season and with Willa?

In general, you have warmer waters, [which] provides more fuel for storms. I would say that certainly, yes, that will not help things. But it's not as simple and straightforward as saying you're warming the ocean's surface, you're going to have stronger hurricanes. Other factors also come into play. When you warm up the atmosphere caused by climate change, you warm up the entire atmosphere, not just the surface of the ocean, which removes a little the simple warming of the ocean surface.

This year, we had very low shear, probably due to conditions similar to those of El Niño. And El Niño is mostly a natural event that has occurred since men have lived on the planet, and probably before. People want to say, "Humans are responsible for eight percent." But it's really hard to say with certainty in this regard.

I'm worried about the rise in sea level: even though the storms do not change in intensity, if, for example, the sea level is 6 inches higher than the sea level. previously, you will receive more floods, especially where the coast goes up very gradually. And also I think there is a lot of evidence showing that these storms will bring more rain. Obviously, Florence and Harvey are extreme examples, but we expect that to happen in the long run.

What do you want people to know about Willa?

It's a serious storm, it's going to land tomorrow. You have a Florence and an Irma, and people say to themselves, "Oh, you have two weeks to announce the coming of a hurricane." And that's not always the case. Sometimes these storms happen very quickly – and we saw that with Michael and Willa as well. The storms that hit Mexico in Mexico at this time of year are quite common, but it is obvious that it will be quite strong. So we will just have to hope and pray that it will weaken before it hits. We have a little more than a day. If people were on site, follow the advice of the local emergency management, they know the storm is there and will be the best on the ground to advise you on what to do.