Typhoon Kalmaegi Kills 114 in Philippines; Fung‑Wong Looms — Hurricanes, Typhoons and Cyclones Explained

WASHINGTON — Typhoon Kalmaegi has killed at least 114 people in the Philippines and left many more missing before moving into Vietnam on Friday. A second storm, Typhoon Fung‑Wong, is expected to reach the Philippines around Sunday and is forecast to strengthen into a major typhoon.

Some facts about typhoons

Hurricane? Cyclone? Typhoon?

They are all the same type of storm — tropical cyclones — but different regions use different names. Hurricane is used in the Atlantic, Caribbean Sea and the central and northeast Pacific. In the northwest Pacific these storms are called typhoons. In the Bay of Bengal and the Arabian Sea they are referred to as cyclones. The term tropical cyclone is common in the southwest Indian Ocean, while the southwestern Pacific and southeastern Indian Ocean often label very strong systems as severe tropical cyclones.

Strength

A system is given a name and classed as a tropical storm once sustained winds reach 39 mph (63 kph). It becomes a hurricane, typhoon or cyclone when sustained winds reach 74 mph (119 kph). Forecasters categorize storms into five intensity categories based on wind speed; Category 5 begins above 155 mph (249 kph). Australia uses a different scale for categories.

Officials said Kalmaegi was on the stronger side for typhoons. Reports listed maximum winds of about 132 mph (213 kph) with sustained surface winds near 93 mph (150 kph) in parts of the Philippines. Globally, the highest recorded tropical cyclone winds were in 2015's Hurricane Patricia in the eastern Pacific, while Typhoon Tip in 1979 had the lowest recorded central pressure — an important measure of storm intensity.

Rotation

Storms north of the equator rotate counterclockwise; storms south of the equator rotate clockwise, due to the Coriolis effect.

Season

Hurricane and cyclone seasons vary by basin. The Atlantic and central Pacific seasons run June 1 through November 30. The eastern Pacific runs May 15 through November 30. The northwest Pacific can produce storms nearly year‑round but is busiest from May through November. The south Pacific and Australian cyclone season runs November through April, and the Bay of Bengal typically has two active periods: April to June and September to November. Vietnam frequently experiences landfalling typhoons around this time of year.

The busiest basin

The northwest Pacific — where Kalmaegi struck — is the planet's most active basin because warm water persists year‑round, upper‑level winds are often weak, and frequent thunderstorm activity seeds storm development, said Kristen Corbosiero, professor of atmospheric and environmental sciences at the University at Albany.

By this point in the year the northwest Pacific averages about 23 named storms, 14 of which become typhoons; a typical year sees roughly 27 named storms, according to Colorado State University's storm database. Kalmaegi and Fung‑Wong are the 26th and 27th named storms this season, with Kalmaegi the 15th typhoon. Although named storms have been slightly more numerous than average, Corbosiero said the season has been generally weaker overall: a combined metric of storm strength, frequency and duration indicates the season is about 62% of normal so far. Kalmaegi ranks as the fourth‑strongest typhoon of the season.

For comparison, the Atlantic averages about 14 named storms a year; this season there have been 13 so far, and the most recent — Hurricane Melissa — caused major damage in Jamaica and Cuba.

What helped these storms form

Warm ocean waters are necessary but not always sufficient to start a tropical cyclone. Atmospheric patterns matter too. One important driver is the Madden‑Julian Oscillation (MJO), a tropical wave pattern that originates near the Indian Ocean and travels eastward, enhancing rainfall and storm activity ahead of it while suppressing activity behind. The MJO can circle the globe every 30 to 60 days.

A strong MJO pulse can spur tropical cyclone formation. It boosted activity in the northwest Pacific earlier in the season, subsided as it moved east, and a strong pulse has recently passed through again — contributing to the formation of Kalmaegi and Fung‑Wong, Corbosiero said. That same MJO is currently near the international date line and may reach the Atlantic in about one and a half to two weeks, where it could help generate late‑season tropical activity.

How names are chosen

Name lists are maintained by the World Meteorological Organization and reflect names familiar in each region. When a storm causes extensive deaths or damage, its name is retired and replaced — for example, Katrina was retired after the catastrophic 2005 U.S. landfall. The Philippines also maintains a separate naming system; locally, Typhoon Kalmaegi is known as Tino.

Sources: Colorado State University, University at Albany, Joint Typhoon Warning Center, World Meteorological Organization, National Oceanic and Atmospheric Administration, Weather Underground.

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