Hurricane Nora (1997)

Infobox Hurricane
Name=Hurricane Nora
Type=hurricane
Year=1997
Basin=EPac
Image location=Hurricane Nora (1997) GOES.jpg


Formed=September 16, 1997
Dissipated=September 26, 1997
1-min winds=116
Pressure=950
Da

Fatalities=2 direct, 4 indirect
Areas=Baja California, southwestern United States
Hurricane season=1997 Pacific hurricane season

Hurricane Nora was the fourteenth named tropical cyclone and seventh hurricane of the 1997 Pacific hurricane season. The September storm formed off the Pacific coast of Mexico, and aided by waters warmed by El Niño, eventually peaked at Category 4 intensity on the Saffir-Simpson Hurricane Scale.

Nora intensified and weakened quickly before taking an unusual path, which lead it to make landfall twice as a hurricane in Baja California. After landfall, its remnants affected the Southwestern United States with tropical storm-force winds, torrential rain and flooding. Nora is blamed for two direct casualties in Mexico, as well as substantial beach erosion on the Mexican coast, flash flooding in Baja California, and record precipitation in Arizona. Nora persisted far inland; it was only the third known tropical cyclone to reach Arizona while tropical.

Meteorological history

Nora formed early on September 16, 1997, 290 miles (460 km) southwest of the Mexican port of Acapulco, Guerrero, from the same tropical wave that had earlier created Hurricane Erika. Due to favorable conditions associated with El Niño,cite journal |author=Farfán, Luis M. and Joseph Zehnder|month = August | year = 2001 | title=An Analysis of the Landfall of Hurricane Nora | journal = Monthly Weather Review | format=PDF | accessdate=2006-02-26 | volume = 129 | issue 8 | url=http://ams.allenpress.com/archive/1520-0493/129/8/pdf/i1520-0493-129-8-2073.pdf] the tropical disturbance quickly achieved deep convection and became well-organized. By 6 a.m. UTC, the U.S. National Hurricane Center had designated the disturbance as Tropical Depression Sixteen-E. Half a day later, it had gained enough strength to be named Tropical Storm Nora.cite web| publisher =National Hurricane Center | date = October 30, 1997 | title = Preliminary Report: Hurricane Nora: 16 – September 26, 1997 | author = Rappaport, Edward N. | accessdate=2006-02-20| url=http://www.nhc.noaa.gov/1997nora.html]

A high pressure area over northern Mexico forced the storm to move west-northwest for the first few days. During that time, Nora kept intensifying, becoming a Category 1 hurricane on the Saffir-Simpson Hurricane Scale by noon UTC on September 18. Next, Nora slowed and became stationary for two days from September 18. The eye vanished, and convection began to decrease. This was presumed to have happened because of a drop in sea-surface temperatures. The cool waters temporarily weakened Nora's winds to 75 mph (120 km/h) down from a maximum of 105 mph (165 km/h). After leaving the area of cool waters, Nora began moving nearly parallel to Mexico's western coast. There was a period of rapid intensification and the eye reappeared. Cloud tops cooled and at midday UTC on September 21, Nora reached its peak intensity of 950 mbar and 135 mph (210 km/h) winds, a Category 4 hurricane. The peak was brief as Nora then encountered cool waters in the wake of Hurricane Linda. They weakened Nora's winds to 80 mph (130 km/h) by September 23 and broke its eyewall.

Nora then crossed an area of abnormally warm water near the west coast of the Baja California Peninsula. It restrengthened slightly before making its first landfall near Bahía Tortugas, Baja California Sur.es icon cite web| author=Servicio Meteorológico Nacional (Mexico)| year=1997| title=Huracán Nora| publisher=Comisón Nacional del Agua| accessdate=2006-02-21| url=http://smn.cna.gob.mx/ciclones/tempo1997/pacifico/nora/nora.html] When Nora was inland, the area of the storm located in the Gulf of California began to reintensify. Hurricane Nora then made a second landfall about 60 miles (95 km) south-southeast of San Fernando, Baja California.

At landfall, a trough was accelerating Nora northwards, causing it to reach a forward speed of 30 mph (50 km/h). Late on September 25 (UTC), still a tropical storm, it entered the continental United States at the California-Arizona state line. Nora began to weaken rapidly, and was downgraded to a tropical depression three hours later, while located between Blythe and Needles, California.cite journal | author = Lawrence, Miles B. | title = Eastern North Pacific Hurricane Season of 1997 | url = http://ams.allenpress.com/archive/1520-0493/127/10/pdf/i1520-0493-127-10-2440.pdf | format = PDF | month = October | year = 1999 | volume = 127 | issue = 10 | pages = 2448 – 50 | accessdate = 2006-12-18 | journal = Monthly Weather Review] Nora reached Arizona while still tropical, becoming the third known system to do so.cite web|author=Flood Control District of Maricopa County|year=1997|title=TS Nora Storm Report|accessdate=2006-02-26|url=http://156.42.96.39/alert/nora/nora_rpt.html] Nora degenerated over land, and the low-level center moved towards the north-northeast. A remnant circulation aloft persisted, however, and was likely responsible for a period of near hurricane-force winds observed at the NWS Cedar City, Utah Doppler weather radar. The remnants gradually became more diffuse over the following two days while moving generally northeastward, through portions of Utah, Colorado, Idaho and Wyoming.

Preparations

While Nora stayed off the Pacific coast of Mexico, the "Servicio Meteorológico Nacional" (National Meteorological Service) issued a hurricane watch for the coast between Lázaro Cárdenas, Michoacán, and Puerto Vallarta, Jalisco, and several major ports in the shoreline closed to navigation.cite news|title=North-moving Nora lashes Baja's southern tip|publisher=Associated Press|date=September 23, 1997|accessdate=2006-04-10|url=http://www.cnn.com/WEATHER/9709/23/nora.mexico/index.html] As the storm moved away from the mainland coast and towards the Baja California Peninsula, about 500 people were evacuated from their homes near Cabo San Lucas, Baja California Sur, and placed in shelters to prepare for the storm's impact. At the same time, in Sonora, another 50 were evacuated from a fishing camp in Guaymas.cite news|title=Hurricane Nora lashes Baja California|publisher=Associated Press|date=September 24, 1997|accessdate=2006-05-11| url=http://www.cnn.com/WEATHER/9709/23/nora/index.html] Meanwhile, the SMN issued tropical storm warnings along the Baja California coast, as well as hurricane watches and warnings around the entire Gulf of California between Santa Rosalía, Baja California Sur, and Bahía Kino, Sonora.cite news|title=Hurricane Nora to hit Baja Thursday morning|publisher=Associated Press|date=September 25, 1997| accessdate=2006-05-11|url=http://www.cnn.com/WEATHER/9709/24/nora.pm/index.html]

In September 24, Arizona Governor Jane Dee Hull activated an emergency response center to prepare the state's response to the flash flooding the storm would cause on the dry desert floor, and Yuma residents began to fill approximately 55,000 sandbags to contain the possible flooding. [cite news|title=Hurricane Nora nears Mexico|publisher=Associated Press|date=September 24, 1997| accessdate=2006-05-11|url=http://www.cnn.com/WEATHER/9709/24/nora.update.2p/index.html] Hull also activated the state's National Guard, and sent drinking water and electric generators to Yuma.cite news|title=Nora weakens, but heavy rains threaten U.S.|publisher=Associated Press|date=September 25, 1997| accessdate=2006-05-11|url=http://www.cnn.com/WEATHER/9709/25/nora1130a/] Further inland, the National Weather Service issued flash flood watches for western Arizona, southeastern California, southwestern Colorado, southern Nevada and southern Utah on September 26. [cite web|author=Hydrometeorological Prediction Center|publisher=NOAA|title=Storm Summary for Tropical Depression Nora, 4 a.m. EDT September 26, 1997|accessdate=2006-03-06| url=http://www.hpc.ncep.noaa.gov/tropical/1997/nora/92606ns1.html]

Impact

Hurricane Nora caused two direct deaths in Mexico and three or four indirect ones in the United States. Although the total cost of damage is not known, Nora caused up to several hundred millions of dollars of damage. The system also dumped heavy rain in the United States and Mexico, which caused flooding and power outages.

Mexico

Nora killed two in Mexico: an electrocution by a downed power line in Mexicali, Baja California, and a diver caught in strong underwater currents created by Nora off the coast of the San Quintin Valley.

Although Nora's center of circulation remained well offshore from southwestern mainland Mexico, the Associated Press reported that waves to convert|20|ft|m hit that coastline, destroying dozens of homes.cite news|title=Hurricane Nora lashes Mexico's Pacific coast|publisher=Associated Press|date=September 22, 1997| accessdate=2006-05-11|url=http://www.cnn.com/WEATHER/9709/22/nora/index.html] Nora's winds also produced rough seas and high waves, which caused in substantial beach erosion, particularly around Acapulco, where the Pie de la Cuesta beaches were washed away. In the states of Guerrero and Jalisco, Nora tore down trees and washed away the foundations of homes, albeit without causing any injuries.

Heavy rains also fell along its northeast periphery, with the highest amounts of convert|20.94|in|mm falling at La Cruz/Elota and convert|16.79|in|mm being measured at Ligui/Loreto. [Hydrometeorological Prediction Center. [http://www.hpc.ncep.noaa.gov/tropical/rain/nora1997.html Hurricane Nora - September 14 – 28, 1997.] Retrieved on 2007-01-04.] About 350 to 400 people were left homeless by floodwaters in the town of Arroyo de Santa Catarina in northern Baja California. Heavy damage and flooding was reported in San Felipe, on the northwestern shore of the Gulf of California, as well as extensive beach erosion. Local roads and highways were destroyed and the town's dock was severely damaged.cite web | publisher = San Felipe, Baja California Official Website | title = Hurricane Nora, San Felipe, Baja California | month = September | year = 1997 | accessdate=2006-03-29 | url = http://www.sanfelipe.com.mx/nora9247/summry1015.htm] On the northeastern shore, at Puerto Peñasco, Nora blew down trees, billboards, electric wires, taco stands, and ripped sheet-metal from homes. Waves of convert|10|ft|m were reported there.

United States

In the United States, there were no direct deaths blamed on the hurricane. However, the California Highway Patrol attributed three or four traffic fatalities in southern California to the weather. [cite news|title=Nora gives Arizona a soaking|publisher=Associated Press|date=September 25, 1997| accessdate=2006-05-11|url=http://www.cnn.com/WEATHER/9709/25/nora/]

Damage totals in the United States are not fully known but media summaries of Nora included a loss to agriculture preliminarily estimated at several hundred million dollars, and at least one study places the figure at $150 – 200 million (1997 USD).cite web|author=National Drought Mitigation Center|title=Reported Effects of the 1997 – 98 El Niño|publisher=University of Nebraska-Lincoln|accessdate=2006-02-26 | url=http://www.drought.unl.edu/whatis/elninoanalysis.pdf] About a $30–40 million (1997 USD) loss to lemon trees was estimated.cite web | author=National Climatic Data Center | title=NCDC Event Details | date=September 25, 1997 | accessdate=2006-07-08 | publisher = NOAA | url=http://www4.ncdc.noaa.gov/cgi-win/wwcgi.dll?wwevent~ShowEvent~287830] Even though Nora had long lost hurricane strength, near hurricane-force winds were felt at the Dixie National Forest in southwestern Utah, where strong gusts sheared off the tops of large trees. [cite web | author = Cooperative Program for Operational Meteorology, Education and Training | title = Nora: After Landfall (VIS) | publisher = University Corporation for Atmospheric Research | accessdate=2006-04-10 | url=http://www.comet.ucar.edu/nsflab/web/explore/n4vis.htm]

The Yuma radar indicated a small area with near convert|10|in|mm of rain along the northern Gulf of California coast of Baja California. In the United States, the largest total rainfall was recorded at the Harquahala Mountains in Arizona, where convert|11.97|in|mm of rainfall were recorded as a result of Nora, causing flash floods in western Arizona.

Near Phoenix, rainfall from the storm caused the Narrows Dam, a small earthen dam, to fail. In other locations in Arizona, California, Nevada, and Utah, more than convert|3|in|mm occurred in a few localized areas, sometimes with precipitation comparable to the entire local yearly average rainfall. Flooding was also reported in Somerton, San Diego, El Centro, Palm Springs and Indio, while 12,000 people lost power in Yuma,cite web|author=Rebecca Carter|year=2002|title=Tropical Storm Impacts on Arizona and New Mexico|accessdate=2006-03-03|publisher=Climate Assessment for the Southwest Project, Institute for the Study of Planet Earth, University of Arizona| url=http://www.ispe.arizona.edu/climas/forecasts/articles/tropical_Aug2002.pdf] as well as Los Angeles and southwestern Utah.

Despite the damage, the World Meteorological Organization did not retire the name "Nora" during its meeting in the spring of 1998. As a result, it was used in the 2003 Pacific hurricane season and is on the list of names to be used in 2009.

See also

* List of Pacific hurricanes
* List of Arizona hurricanes
* List of California tropical storms
* List of wettest tropical cyclones in Arizona

References

External links

* [http://www.nhc.noaa.gov/1997nora.html NHC Nora Report]
* [http://www.hpc.ncep.noaa.gov/tropical/rain/nora1997.html HPC rainfall report on Nora]
* [http://rsd.gsfc.nasa.gov/goes/pub/goes/QTmovies/9709.nora.mov GOES-8 movie of Hurricane Nora]