THE SAN DIEGO HURRICANE OF 2 OCTOBER 1858 BY MICHAEL CHENOWETH AND CHRISTOPHER LANDSEA The discovery of a hurricane that directly impacted San Diego, California, nearly 150 yr ago has implications for residents and risk managers in their planning for extreme events for the region. ropical cyclones forming in the eastern North 10 September 1976 in California and Arizona, and Pacific Ocean are occasional visitors to the Hurricane Nora in September 1997 in Arizona. Only Tsouthwestern United States. By the time these the 1939 tropical storm made a direct landfall in coastal systems travel far enough to the north to bring their California (Smith 1986), because the other three sys- associated moisture to the United States, the tropical tems entered the United States after first making land- cyclones have normally diminished below tropical fall in Mexico. storm strength over Mexico or over the colder waters The 1939 tropical storm caused $2 million in prop- of the California Current that flows southward along erty damage in California, mostly to shipping, shore the California coast. Rain, sometimes locally excessive, structures, power and communication lines, and crops. is frequently observed in many areas of the southwest- Ships in coastal waters of southern California reported ern United States when tropical cyclone remnants en- southeast winds between 34 and 47 kt (Hurd 1939). ter the region (Blake 1935; Smith 1986). However, no tropical cyclones are recorded or esti- Four tropical cyclones have managed to bring tropi- mated to have made landfall in the southwestern cal storm-force winds to the southwestern United United States as a hurricane, with maximum 1-min States during the twentieth century: a tropical storm surface (10 m) winds of at least 64 kt. A list of the docu- on 25 September 1939 in California, Hurricane Joanne mented tropical cyclone remnants to affect the south- on 6 October 1972 in Arizona, Hurricane Kathleen on western United States can be found in Smith (1986). Extreme rain events in the southwestern United States and heavy rains are the most frequent effect of tropical cyclones in the region. High winds and coastal AFFILIATIONS: CHENOWETH—Elkridge, Maryland; LANDSEA—NOAA/ storm-surge and wave action are much less frequent. AOML/Hurricane Research Division, Miami, Florida Smith (1986) states: "The occurrence of sustained winds CORRESPONDING AUTHOR: Christopher Landsea, NOAA/ of even hurricane intensity, 65 kn[ots], is extremely AOML/Hurricane Research Division, 4301 Rickenbacker Causeway, Miami, FL 33156 unlikely anywhere in the Southwest." E-mail: [email protected] Recently, the first author discovered the existence DON 0.1 175/BAMS-85-1 1-1689 of a hurricane at San Diego, California, on 2 October In final form 27 June 2004 1858 in newspaper accounts from California. This hur- ©2004 American Meteorological Society ricane is perhaps not unknown to local historians of the area, but its existence has been unknown or apocry- AMERJCAN METEOROLOGICAL SOCIETY NOVEMBER 2004 BAFft I 1689 Unauthenticated | Downloaded 10/05/21 03:17 PM UTC phal at best, to the meteorology community until now. lyze the Atlantic basin hurricane database (Landsea et al. The existence of this hurricane and its damaging effects 2004a). This work seeks to go back in time and to re- on land are of interest to meteorologists interested in visit and revise, if necessary, the official tracks and in- the unique alignment of atmospheric events that tensities of tropical storms and hurricanes from 1851 brought such a powerful storm so near to land. Prop- to the present. Currently, alterations and additions erty insurers, local governments, and others interested have been made for the period of 1851-1910, as well in risk assessment may well find a need to reconsider as for 1992's Hurricane Andrew (Landsea et al. 2004b). the risks for a hurricane strike in southern California. In this paper, we present the newspaper accounts DATA SOURCES. Data sources include microfilm of the storm in southern California. To these reports copies of daily weather observations made by the U.S. we add the meteorological observations for the region Army medical staff at the various army posts through- made by the U.S. Army, U.S. Coast Survey, and pri- out the United States (Fleming 1989), microfilm cop- vate individuals to reconstruct the large-scale synoptic ies of California newspapers, and original U.S. Coast pattern. Damage reports are examined in respect to survey notebooks. The U.S. Army and U.S. Coast methods for estimating wind speed from poststorm Survey notebooks are kept at the U.S. National Ar- surveys of the resulting damage caused by tropical cy- chives in College Park, Maryland. Newspaper records clones and tornadoes. The merging of all data sources are held by the U.S. Library of Congress Newspaper leaves no doubt as to the tropical origin of this storm. Library. Documentation of a northeast Pacific hurricane to Newspaper accounts from the Daily Alta California impact San Diego parallels ongoing efforts to reana- (San Francisco) and the Los Angeles Star provide the FIG. I. Location of weather station data and other sites mentioned in newspaper accounts used in this study. All labeled sites are U.S. Army or Smithsonian Institution observers except for Visalia, San Luis Obispo, Santa Barbara, Los Angeles, and San Pedro. (The town of El Monte, immediately east of Los Angeles is not labeled.) 1690 I BAflS- NOVEMBER 2004 Unauthenticated | Downloaded 10/05/21 03:17 PM UTC only surviving records. However, the Daily Alta Cali- TABLE 1. The wind-force scale in use by the U.S. fornia carried press items from other newspapers, in- Army (adopted from Smithsonian Institution cluding the San Diego Herald, providing crucial details practices) in 1858. Note the absence of calm on the storm. winds as a separate category. Survey notebooks of the U.S. Coast Survey were consulted, but no data for October 1858 were found. 1. Very light breeze 2 mph (2 kt) Likewise, a check of Comprehensive Ocean-Atmosphere 2. Gentle breeze 4 mph (3 kt) Data Set (COADS) marine data (Woodruff et al. 1987) from the region did not provide any information on 3. Fresh breeze 12 mph (10 kt) the hurricane's origin or subsequent track. Figure 1 4. Strong wind 25 mph (22 kt) depicts a map of the western United States and the location of U.S. Army, and other locations where daily 5. High wind 35 mph (30 kt) weather observations are available for October 1858. 6. Gale 45 mph (39 kt) METHODS. We compiled all available weather data 7. Strong gale 60 mph (52 kt) and produced thrice-daily weather maps (0700, 1400, 8. Violent gale 75 mph (65 kt) and 2100 LT) for each day from 1 to 3 October 1858. 9. Hurricane 90 mph (78 kt) The shipping news from the newspapers and COADS did not provide data with ship positions (newspapers) 10. Most violent hurricane 100 mph (87 kt) or data in the region (COADS) so that the analysis is based on land observations only. Data from Mexico are not available except in the southern reaches of the curate reference frames for wind calibration were not country at Mirador (near Vera Cruz on the Gulf of generally available in the mid-nineteenth century. As Mexico coast). Barometric pressure data for Sacra- late as 1890, the highest standard velocity for calibra- mento (38°35 'N, 121°28 "W), San Francisco (37°48 'N, tion was 35 mph by whirling machine (Ferguson and 122°25'W), and New San Diego (32°41 'N, 117°13 'W) Covert 1924). The low frequency of hurricane-force were adjusted for elevation, instrument temperature, winds also makes it difficult to subjectively estimate and standard gravity (List 1951). These readings should wind speed without the aid of instruments. be considered reliable only with a ±2-4 mb uncertainty We use the Saffir-Simpson hurricane scale of wind because metadata are not complete or independently speed (Saffir 1973; Simpson 1974) and the Fujita scale confirmed.1 Wind-force estimates, based upon visual (Fujita 1971) to equate typical destructive effects of observations at U.S. Army posts, were made accord- high wind speeds on land to independently estimate ing to a scale included in the printed form used for the wind speed at San Diego. These estimates take into recording daily weather observations (Table 1). Some consideration modifications of Fujita's original system caution is required in interpreting these values with used in more recent research of hurricane damage reference to modern values. Because the modern defi- (Boose et al. 2001). Other weather elements, such as nition of wind speed in the United States is based on temperature, are given as recorded but, because the instrumental 1 -min averages, and the methods used temperature readings were made in nonstandard ex- in the mid-nineteenth century are unknown, the val- posures (Chenoweth 1993), there is a potential for ues cannot be considered equivalent. Additionally, ac- a warm bias in daytime temperatures due to radia- tion reaching unscreened thermometers. At night, these biases are smaller unless artificial heat reaches 1 List (1951) is used for the reduction of the mercury column to the instrument. standard temperature (16.7°C). The attached thermometer readings were from 18° to 27°C, which gives a range of The general absence of pressure data, and the varied corrections between -3.3 and -4.7 mb. The correction for topography of the western United States, makes the daily standard gravity for the latitude of San Diego is between -0.7 weather map analysis incomplete but the best possible and -1.0 mb. These two adjustments overwhelm the positive from available sources.