# Why doesn’t the west coast (USA) ever get hurricanes? **URL:** \ **Category:** Factual Questions\ **Created:** [June 8, 2002, 2:34pm UTC](https://boards.straightdope.com/t/why-doesn-t-the-west-coast-usa-ever-get-hurricanes/112971 "2002-06-08T14:34:10Z")\ **Posts on this page:** 14\ **Page:** 2
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [June 9, 2002, 12:21am UTC](https://boards.straightdope.com/t/why-doesn-t-the-west-coast-usa-ever-get-hurricanes/112971/21 "2002-06-09T00:21:18Z")
> [@](#): > > 1. We here on the west coast are not the wimps of the eastern seaboard. 100mph winds happen every winter just off the coast. Sometimes they come inland. We merely don’t get all excited about them. Also, the eastern media doesn’t care what happens on the other side of the country so little news coverage. Because they’re not hurricanes. They are not tropical storms and as a result do not have the rains that tropical storms have. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [June 9, 2002, 12:22am UTC](https://boards.straightdope.com/t/why-doesn-t-the-west-coast-usa-ever-get-hurricanes/112971/22 "2002-06-09T00:22:59Z")
> [@](#): > > We here on the west coast are not the wimps of the eastern seaboard. 100mph winds happen every winter just off the coast. The interesting topography of the Mojave area, the foothills of the Sierra Nevada running north-south and the Tehachepi (or however it’s spelled) range running east-west, creates a natural “venturi” pointed right at the town of Mojave. This is very useful for the electricity generating windmills in the area. Sometimes Mojave gets hit with 100mph winds. Although the events make the local paper (the _Antelope Valley Press_) it’s not really a big “news” event. They mention the winds on the local news sometimes though. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [June 9, 2002, 12:24am UTC](https://boards.straightdope.com/t/why-doesn-t-the-west-coast-usa-ever-get-hurricanes/112971/23 "2002-06-09T00:24:48Z")
Of course, there is no danger of a “storm surge”. Not that I’ve been in one, but that sounds like the more dangerous part of a hurricane. ---
**Author:** ![Viscera](https://avatars.discourse-cdn.com/v4/letter/v/258eb7/32.png) [@Viscera](https://boards.straightdope.com/u/Viscera)\ **Post date:** [June 9, 2002, 6:31am UTC](https://boards.straightdope.com/t/why-doesn-t-the-west-coast-usa-ever-get-hurricanes/112971/24 "2002-06-09T06:31:31Z")
**barbitu8** asks: > [@](#): > > Originally posted by Viscera > They are also called “cyclones” in the Pacific, south of the Equator. > > > [@](#): > > > > Source? According to Van Nostrand’s Scientific Encyclopedia tropical cyclones are only found in the Indian Ocean area. It states that these are the most intense and feared storms, with winds exceeding 175 knots (200 mph) having been measured. Currently I work with the Air Force, doing tropical cyclone intensity/position estimates using satellite imagery. In the south Pacific, for US interests, the Joint Typhoon Warning Center (in Honolulu, the official warning agency for the US) calls them Tropical Cyclones. The Australian Bureau of Meteorology also calls them Cyclones in their areas of responsibility in their warnings. The strongest storms that have been measured on Earth have occurred in the western Pacific ocean. However, there is very little data over the entire Indian ocean (except for satellite imagery). Storms that occur in the Bay of Bengal are feared though, due to the fact that they can develop and intensify extremely rapidly. This coupled with the extremely populous areas to the north, disaster strikes frequently unfortunately. **Doghouse Reilly** asked about a comparative wind scale. In the south Pacific and Indian Oceans, any storm with winds of 35 knots or greater (39 mph, Tropical Storm Force winds) is called a Tropical Cyclone. The storms are numbered, but receive names from the Australians, or the French (in the central and western Indian oceans). Storms that cross from the Aussie area to the French area will keep both names. The storms in the northern Indian Ocean don’t have names. In the Northeast Pacific, and Atlantic oceans, you have your familiar storm intensities, Tropical Storms (35-65 knots), and Hurricanes (65+ knots). In the Northwest Pacific, for US interests, you have Tropical Storms (which are numbered). They are only named when the Japan Meteorological Agency deems the storm a tropical storm. Typhoons are the same as hurricanes (65+ knots or greater wind speeds). Super typhoons are storms that have max sustained winds of 127 knots or greater. Sorry for the long response. Vis ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [June 9, 2002, 1:23pm UTC](https://boards.straightdope.com/t/why-doesn-t-the-west-coast-usa-ever-get-hurricanes/112971/25 "2002-06-09T13:23:05Z")
Ahh, living in Australia’s Tropical North, I can attest to the fact that they are called cyclones in this area of the world. **Viscera** has the Straightdope! ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [June 9, 2002, 5:21pm UTC](https://boards.straightdope.com/t/why-doesn-t-the-west-coast-usa-ever-get-hurricanes/112971/26 "2002-06-09T17:21:20Z")
This is due to the dual meaning of “cyclone.” Cyclone means a low-pressure area. All lows are cyclones. However, when referring to hurricanes, it is the Indian Ocean area that refers to that particular atmospheric event as a cyclone. When you refer to tropical cyclones, again there is the same ambiguity. Tropical cyclone can mean any tropical disturbance, but in the sense we have been using it here, and in regards to the OP, it refers to a hurricane in the Indian Ocean area. ---
**Author:** ![whitetho](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whitetho/32/1059_2.png) [@whitetho](https://boards.straightdope.com/u/whitetho)\ **Post date:** [June 9, 2002, 6:01pm UTC](https://boards.straightdope.com/t/why-doesn-t-the-west-coast-usa-ever-get-hurricanes/112971/27 "2002-06-09T18:01:49Z")
> [@](#): > > \*Originally posted by Johnny L.A. \* > \*\*Of course, there is no danger of a “storm surge”. Not that I’ve been in one, but that sounds like the more dangerous part of a hurricane. \*\* Here in North Carolina they recently researched what was causing hurricane fatalities, and they concluded that the danger from the storm surge, which is a rise in the ocean level as the storm comes ashore, was less of a problem than thought. Nowadays we generally have enough warning to evacuate the low-lying sections which are most at risk. The study concluded that the greatest current danger is from inland flash-flooding, most typically when someone tries to drive through a flooded section and gets swept away. ---
**Author:** ![critter42](https://avatars.discourse-cdn.com/v4/letter/c/7ba0ec/32.png) [@critter42](https://boards.straightdope.com/u/critter42)\ **Post date:** [June 9, 2002, 8:37pm UTC](https://boards.straightdope.com/t/why-doesn-t-the-west-coast-usa-ever-get-hurricanes/112971/28 "2002-06-09T20:37:14Z")
> [@](#): > > \*Originally posted by barbitu8 \* > \*\* > > Now, if anyone is interested I’ll explain, as far as I know, the characteristics of a tropical storm and how it differs from a non-tropical or extra-tropical storm. But you have to ask me nicely.🙂 \*\* Actually, I’m a little more curious in a phenomena that has been occurring with greater frequency the last couple of years on the East Coast - a storm that the forecasters call a “hybrid” - it has tropical and extra-tropical characteristics. Having lived in Norfolk, VA the last decade, I really understand that there is a distinct difference between a hurricane/Trop. Storm and a Nor’easter - however, as I noted, there have been a couple of storms over the last couple of years that apparently exhibit both tropical and extra-tropical characteristics, but nobody ever went into more detail than that. If anyone can give a good explanation (you can use heavy-duty meteorological language, but limit the math please 🙂 ) about what the forecasters mean by this type of storm, and how it differs/is the same as a tropical and an extra-tropical storm, I would greatly appreciate it. (in politest voice possible) - So, **barbitu8** , it would be really kind and nice of you to explain this, and you would be considered by at leat one person one of the greatest board posters ever! _(stage whisper) - psst - think he’ll buy it?_ critter42 ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [June 9, 2002, 9:44pm UTC](https://boards.straightdope.com/t/why-doesn-t-the-west-coast-usa-ever-get-hurricanes/112971/29 "2002-06-09T21:44:57Z")
For years, \*\* CRITTER42 \*\*, I’ve wondered about this too and exactly what are the characteristics of a “tropical” storm. After coming to the conclusion that it is not one that wears a Panama hat, I’ve been able to deduce the following. Before one can understand what a hybrid is, one has to know what a tropical storm is. Basically, a tropical storm is what they call adiabatic, occuring without gain or loss of heat. It gets its energy from water. The water temperature has to be a minimum of 80-81 degrees F to support a hurricane. The low pressure above has to merge with a surface low to form one continuous vertical low pressure, causing the air to rise from the sea to a great height. In a non-tropical low system, the isobars are not concentrated into a tight center. There is a center to these storms, of course, but the barometic pressure does not continuously fall as you approach the center. There are variations in the continuous drop of pressure as you approach the center. It is the gradient between isobars that causes wind. In a tropical storm, the pressure is lowest at the center, and when a eye develops, the winds rotate around this center, sucking up the water and forming the eyewall. Around the exact center, there is not much wind because the winds have to rotate around a point. Surface pressure in a hurricane is very low at the eye, but rises rapidly outward. Because of this large pressure gradient, winds are of high velocity. In the northern hemisphere, the NE quadrant is where the velocity of the wind and the velocity of the storm are additive. Characteristics of a tropical storm are as follows. Ordinary storms are associated with fronts. Tropical storms are not. They derive their energy from convective instability and condensation of copious quantities of water. The lowest pressure is at the center, and the pressure rises as you move outward. When a storm does not have all the characteristics of a tropical storm, it is called a hybrid or extra-tropical. The usual situation later in the year is the situation where a hurricane heads for Maritime Canada or England. It passes over water which is below 80F and begins to lose the source of its energy: the warm water. Sometimes a cold front will pass over the States and will pick up the tropical storm. In that event, the storm becomes associated with the front and loses its tropical characteristics. As best as I can deduce, a hybrid is a storm that has some of the tropical characteristics, but not all of them. There may be a low pressure aloft, but it does not merge with one at the surface, so you don’t have the convective instability; nonetheless, they are not associated with a front: hence, a hybrid. The water temperature may be below 80 and so you don’t have the condensation of copious quantities of water. ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [June 9, 2002, 10:28pm UTC](https://boards.straightdope.com/t/why-doesn-t-the-west-coast-usa-ever-get-hurricanes/112971/30 "2002-06-09T22:28:16Z")
[http://www.angelfire.com/la3/hurricanecentral/Glossary.html](http://www.angelfire.com/la3/hurricanecentral/Glossary.html) > [@](#): > > Extratropical: > A term used in advisories and tropical summaries to indicate that a cyclone has lost its “tropical” characteristics. The term implies both poleward displacement of the cyclone and the conversion of the cyclone’s primary energy source from the release of latent heat of condensation to baroclinic (the temperature contrast between warm and cold air masses) processes. It is important to note that cyclones can become extratropical and still retain winds of hurricane or tropical storm force. ---
**Author:** ![Viscera](https://avatars.discourse-cdn.com/v4/letter/v/258eb7/32.png) [@Viscera](https://boards.straightdope.com/u/Viscera)\ **Post date:** [June 9, 2002, 11:13pm UTC](https://boards.straightdope.com/t/why-doesn-t-the-west-coast-usa-ever-get-hurricanes/112971/31 "2002-06-09T23:13:41Z")
The main difference between tropical cyclones, and subtropical (sometimes called hybrids) systems is that tropical systems are warm core, while subtropical and extratropical systems are cold core. Warm core refers to the fact that at a given altitude, the center of the storm is warmer than the surrounding air. Cold core is the opposite. **barbitu8** is correct, that hybrids don’t have all the characteristics of tropical cyclones. Usually, systems that are called hybrids are missing the “warm core” feature that would make them tropical cyclones. Subtropical systems are relatively common, and include the infamous “Kona lows” that affect Hawaii. However, there is much we don’t know about subtropical systems, and we don’t even have a reliable way to rate their intensities (unlike tropical systems). Also, since many of them happen in the open oceans, and can be difficult to differentiate from regular mid-latitude cyclones, sometimes it may be easier to “ignore” them, for warning purposes. However, these storms can still have strong winds and high seas. Tropical cyclones actually need high pressure aloft, which creates difluence aloft (air moves away from the storm at upper levels). This in turn increases the low level inflow. Air inside the eye is actually sinking, which is why it is usually clear. Vis ---
**Author:** ![Viscera](https://avatars.discourse-cdn.com/v4/letter/v/258eb7/32.png) [@Viscera](https://boards.straightdope.com/u/Viscera)\ **Post date:** [June 9, 2002, 11:32pm UTC](https://boards.straightdope.com/t/why-doesn-t-the-west-coast-usa-ever-get-hurricanes/112971/32 "2002-06-09T23:32:35Z")
Just wanted to clarify that there are three types of cyclones that we are talking about here. **Tropical** - Warm core, get energy from latent heat condensing. **Extratropical** - Cold core, baroclinic systems. Your typical mid-latitude system, except that it is formed from a former tropical cyclone, and will likely have stronger winds. **Subtropical** - cold core, but will have some warm core characteristics, such as no frontal systems, and are not baroclinic. Subtropical storms can be called hybrids, but just because a storm is called a hybrid, doesn’t mean it is a bona fide subtropical storm. Vis ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [June 10, 2002, 12:24am UTC](https://boards.straightdope.com/t/why-doesn-t-the-west-coast-usa-ever-get-hurricanes/112971/33 "2002-06-10T00:24:24Z")
Thanks, \*\* VISCERA \*\*. Finally someone on this MB that knows something about meteorology. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [June 10, 2002, 5:09pm UTC](https://boards.straightdope.com/t/why-doesn-t-the-west-coast-usa-ever-get-hurricanes/112971/34 "2002-06-10T17:09:39Z")
Some googling from me and Barbitu8 is proven correct. From [here](http://www.infoplease.lycos.com/ce6/weather/A0814395.html): > [@](#): > > A tropical cyclone that has matured to a severe intensity is called a hurricane when it occurs in the Atlantic Ocean or adjacent seas, a typhoon when it occurs in the Pacific Ocean or adjacent seas, or simply a cyclone or tropical cyclone when it occurs in the Indian Ocean region. However, in the Australia/New Zealand region, where I live and where my involvement in aviation gives me a keen interest in weather, tropical cyclones of storm strength are always refered to as a cyclone. E.g. [Cyclone Tracy](http://www.stormsignals.com/tracy.htm). Obviously the boundaries between hurricane, typhoon, and cyclone do not strictly follow the boundaries of the relevent oceans. Australia being on the border of the Indian and Pacific Oceans appear to have chosen to call them cyclones (or tropical cyclones) rather than having typhoons on the east coast and cyclones on the west coast. Makes lots of sense!! Australia refers to a tropical cyclone below storm strength as a tropical low. [Previous page](https://boards.straightdope.com/t/why-doesn-t-the-west-coast-usa-ever-get-hurricanes/112971.md?page=1)