Frequently Asked Questions

The use of SHELDUS™ data are limited according to the SHELDUS™ End User License Agreement.

A SHELDUS™ subscription allows users unlimited aggregated data downloads from the SHELDUS™ database for the duration of the current version. Subscriptions only provide access to aggregated data downloads. Pay-as-you-go is available for raw and aggregated data, along with downloads related to named events, PDDs, and GLIDEs. Aggregation is currently not available for named events, PDDs, and GLIDEs. The pricing for pay-as-you-go downloads is determined by the number of database records queried and the per record cost is determined by your account's organizational association (educational/non-profit, local government, federal government, and commercial). Additionally, pay-as-you-go purchases of SHELDUS datasets are a one-time purchase. For more information on pricing, see How To.

A new subscription is required with each annual release of a SHELDUS™ version (e.g., SHELDUS™ 18.0). The annual release used to occur in November, but has recently been moved to the beginning of the calendar year in January. Subscriptions are not valid for 12 months unless they are purchased shortly after a release. Subscriptions are instead tied to database releases and expire upon the release of a new database version. Mid-year updates to a SHELDUS™ version (e.g., 17.1) do not require a new subscription.

We continually update the entire database on an annual basis. Such updates include both changes in the number of records (i.e. additions and deletions), as well as edits to existing records. Thus, no changes in the number of records in a year does not imply that no changes to the data occurred. For example, changes between Version 12 and older (free versions) and Version 14 are significant. The table below highlights these changes--both in the numbers of records as well as in the annual dollar amounts. Version 14 contains nearly 20,000 records and $18 billion in total losses more than Version 12 for the same time period (1960-2012).

The most likely reason is that your subscription to SHELDUS has not been verified. Please check your email inbox for a verification email received from sheldus@asu.edu. Subscriptions should be set-up using official business, agency, or university email accounts.

Aggregating data by county, year/month, and hazard will generate the most highly resolved SHELDUS™ data possible. However, this will still not yield exact record dates or other individual record specific information included in a raw dataset.

The main data sources for the earlier versions of SHELDUS™ were hardy copy versions of "Storm Data and Unusual Weather Phenomena" by the National Climatic Data Center (NCDC). Starting in 2009, SHELDUS™ utilizes digital National Centers for Environmental Information (NCEI) (formerly NCDC) Storm Data records. Geological information also originates from the National Centers for Environmental Information (formerly National Geophysical Data Center) and U.S. Geological Survey. Please see the metadata section for more detailed information.

SHELDUS™ is a loss and hazard database. The National Center’s for Environmental Information Storm Data is an event database. SHELDUS™ includes any event across all types of natural hazards including geological that caused some kind of loss (fatalities, injuries, & property/crop damage). SHELDUS™ can be used to determine the frequency of loss-causing events. NCEI’s Storm Data includes all weather events irrespective of loss, which can be used to determine the frequency of a hazard. SHELDUS™ includes loss and hazard information dating back to 1960 for all 18 hazard types (list can be found on the Metadata page). NCEI’s Online Storm Data dates back to 1960 for tornadoes, thunderstorm wind, and hail only. Reporting for all other NCEI Online Storm Data hazards begins in 1996. SHELDUS™ offers inflation adjustment. This allows for temporal aggregation and comparison of losses over time. NCEI’s Storm Data reports loss values as they occurred at the time. SHELDUS™ applies conservative estimates to losses. Whenever losses are reported as a range (e.g., $5,000 to $50,000), SHELDUS™ selects the lower bound of the range (e.g., $5,000). NCEI reports all events prior to 1994/95 as a range. NCEI’s Online Storm Data offers the midpoint of such a loss range (e.g., $25,000) resulting in a seemingly higher loss than what is reported in SHELDUS™. SHELDUS™ data have been geocoded to allow for spatial aggregation. NCEI’s Storm Data should not be aggregated without further processing – although many users erroneously do.

Reasons why SHELDUS™ data can be aggregated without additional processing steps: For events affecting multiple counties, SHELDUS™ equally distributes loss information across affected counties (including fatalities and injuries). By contrast, NCEI’s Storm Data reports an event’s total loss independent of how many counties were affected, resulting in an overestimation of losses for individual counties.

Events reported by forecast zone: National Weather Service (NWS) forecast zones can consist of multiple counties or parts of multiple counties, especially in mountainous areas. Furthermore, during the 1980s and 1990s, forecast zones were much larger than today and frequently encompassed several counties. SHELDUS™ knows which county belongs to which forecast zone and has tracked these changes over time. Whenever a forecast zone covers multiple counties, SHELDUS™ equally distributes loss information across the counties within the forecast zone. NCEI's Storm Data does not distribute loss information across multiple counties belonging to the same forecast zone, resulting again in an overestimation of losses for individual counties.

Events involving multiple hazards: SHELDUS™ equally distributes loss information across the hazard types. NCEI’s Online Storm Data does not include multiple hazard events.

ASU Center for Emergency Management and Homeland Security (2023). The Spatial Hazard Events and Losses Database for the United States, Version 21.0 [Online Database]. Phoenix, AZ: Arizona State University. Available from https://cemhs.asu.edu/sheldus

This can happen for five reasons:

1. A price for your query is always displayed independent of subscription status.
2. Your subscription may have not been verified, leaving your account inactive for unlimited aggregated data downloads.
3. Your account has been activated but your browser's cache (esp. Google Chrome) does not recognize the change in status. Please delete your browser's cache and sign-in to SHELDUS™ again.
4. Your account has been activated but you did not select one or more of the data aggregation factors found at the end of the query. Please hit submit after you selected one or more aggregation options. A green download button will appear below the last query step. Make sure to scroll down on the website to see the button.
   Without selecting an aggregation factor, the database presumes that you want to purchase raw data, which is not included in a subscription.
5. You selected to download records by PDD, GLIDE, or named event (step #1 of the query). These search options allow only for raw data download, which again is not part of the subscription.

SHELDUS™ is updated annually. Updates can include additional year(s) as well as corrections and/or additions to historic information. This changes the loss information between releases. It is, therefore, strongly recommended to always use the most recent SHELDUS™ release for data analysis.

The asterisk (*) identifies counties that no longer exist. The following changes in regard to counties are reflected in SHELDUS™.

By 1960: There were 3,133 counties and county equivalents.

By 1970: There were 3,142 counties and county equivalents. Princess Ann County, VA was absorbed by Virginia Beach city in 1963. Menominee County, WI was carved out of Shawano County, WI in 1961. Ormsby, NV was consolidated with Carson City/32510 in 1969. Salem, VA/51775 became independent of Roanoke, VA/51161 in 1968. Bedford City, VA/51515 became independent of Bedford, VA/51019 in 1968. Emporia, VA/51595 became independent of Greensville, VA/51081 in 1967. Lexington, VA/51678 became independent of Rockbridge, VA/51153 in 1965. Fairfax City, VA/51600 became independent of Fairfax, VA/51059 in 1961.

By 1980: There were 3,137 counties and county equivalents. Washabaugh, SD/46131 ceased to exist and was added to Jackson, SD/46071 in 1979. City of Nansemond, VA/51123 ceased to exist and was added to City of Suffolk, VA/51800 in 1972. Poquoson/51735 became independent of York County/51199 in 1975. Manassas, VA/51683 became independent of Prince William, VA/51153 in 1975. Manassas Park, VA/51685 became independent of Prince William, VA/51153 in 1975. Dillingham, AK/2070, North Slope, AK/2185 and Valdez-Cordova, AK/2261 were formed. The following Alaska counties ceased to exist: Angoon/2030, Barrow/2040, Cordova-McCarthy/2065, Kenai-Cook Inlet/2120, Kuskokwim/2160, Outer Ketchikan/2190, Prince of Wales/2200, Skagway-Yakutat/2230, Upper Yukon/2250, Valdez-Chitina-Whittier/2260.

By 1990: There were 3,141 counties and county equivalents. La Paz, AZ/04012 was formed from part of Yuma County, AZ in 1982. Cibola, NM/35006 was formed from part of the western portion of Valencia County, NM in 1981. Aleutian Islands, AK/2010 ceased to exist in 1987. Aleutians East, AK/2013 and Aleutians West, AK/2016 were formed from Aleutian Islands in 1987. Lake and Peninsula, AK/2164 was created from parts of Dillingham, AK/2070 in 1989. Northwest Arctic, AK/2188 was formed from Kobuk, AK/2140 and unpopulated parts of North Slope, AK/2185 in 1986. Kobuk, AK/2140 ceased to exist in 1986.

By 2000: There were 3,141 counties and county equivalents. Denali, AK/2068 was formed from parts of Yukon-Koyukuk, AK/2290 and unpopulated parts of Southeast Fairbanks, AK/2240 in 1990. Skagway-Hoonah-Angoon AK/2232 was formed from Skagway-Yakutat-Angoon, AK/2231 in 1992. Yakutat, AK/2282 was formed from Skagway-Yakutat-Angoon, AK/2231 in 1992. Skagway-Yakutat-Angoon, AK/2231 ceased to exist in 1992. Yellowstone National Park, MT/30113 ceased to exist and added to Gallatin, MT/30031 in 1997. South Boston, VA/51780 ceased to exist and was added to Halifax, VA/51083 in 1995. Dade, FL/12025 was renamed to Miami-Date, FL/12086 in 1997.

By 2010: There were 3,143 counties and county equivalents. Broomfield, CO/8014 was formed in parts from Adams, CO/8001, Boulder, CO/8013, Jefferson, CO/8059, and Weld, CO/8123 in 2001. Clifton Forge, VA/51560 ceased to exist and was added to Alleghany, VA/51005 in 2001. Hoonah-Angoon, AK/2105 was formed in 2007. Skagway-Hoonah-Angoon, AK/2232 ceased to exist in 2007. Skagway, AK/2230 was formed from Skagway-Hoonah-Angoon, AK/2232 in 2007. Petersburg, AK/2195 was formed from parts of Wrangell-Petersburg, AK/2280 in 2008. Wrangell-Petersburg, AK/2280 ceased to exist in 2008. Prince of Wales-Hyder, AK/2198 was formed from Prince of Wales-Outer Ketchikan after Outer Ketchikan was annexed by Ketchikan, AK/2130 in 2008. Prince of Wales-Outer Ketchikan, AK/2130 ceased to exist in 2008. Wrangell, AK/2275 formed from parts of Wrangell-Petersburg, AK/2280 and parts of Prince of Wales-Outer Ketchikan, AK/2201 in 2008.

Since 2010: Bedford City, VA/51515 ceased to exist in 2013. Shannon, SD/46113 and Wade Hampton, AK/02270 ceased to exist in 2015.

Source: U.S. Census Substantial Changes to Counties and County Equivalent Entities

Querying simultaneously is the preferred option since there will be no duplicate records. Individual hazard queries can lead to a duplication of losses because the aggregation procedure runs on a singular hazard. For example, a loss event caused by flooding and thunderstorm wind will be returned twice by SHELDUS™ when querying by flooding or wind only in two separate queries. When querying for both hazards in a singular query request, the loss will be split between both hazard types.

Originally, the database did not include U.S. territories. Since the release of SHELDUS Version 18.1, the database includes loss data for all U.S. territories. At this point (Version 20.0), loss information for U.S. territories covers spans from 2000 through 2020.

Your download is a .zip file that contains two .csv files: file A includes direct losses (property, crop, injuries, fatalities) only while file B includes USDA insured crop damage. Depending on your query selection, the download will list the temporal information (year, month, and/or quarter), spatial information (FIPS code, county, state), damage information (crop and property damage, fatalities, injuries), and hazard type(s). Please see the metadata section for more detailed information on the naming convention of table columns

The easiest way to map the downloaded information is to link it using the FIPS code. Spatial information (shapefiles) are available from our products section.

In case of multi-county events, SHELDUS™ distributes losses equally between the affected counties. For instance, a thunderstorm event affecting Richland and Lexington County in South Carolina causing property damages of $50,000 will be entered into the database as an event affecting Richland County with $25,000 and Lexington County with $25,000 worth of damage.

Any time an event, particularly a large scale event, affects multiple counties, SHELDUS™ distributes losses equally. When a query is fairly narrow with a small time window or only few counties, the chance is high that SHELDUS™ returns nearly identical information. Furthermore, between 1960 and 1995, NCDC’s Storm Data provided logarithmic loss estimates ($50, $50-500, $500-5000, $50,000-500,000, $5,000,000-50,000,000, etc.) instead of a specific estimate. In addition, the spatial resolution of historic NCDC Storm Data was low. Damage was frequently reported for larger regions rather than specific counties. This results in seemingly “similar” estimates for many, particularly, historic events given the loss distribution applied by SHELDUS™. Starting in 1995, NCDC’s Storm Data began reporting exact dollar figures and the spatial resolution increased as well. Thus, loss information starting in 1995/96 is spatially and monetarily more accurate than during years prior.

The most likely reason for this problem is that the FIPS code columns are formatted differently. The SHELDUS™ FIPS code column is formatted as text.

SHELDUS™ reflects loss estimates as reported by the NCEI’s Storm Data, etc. We manually match SHELDUS™ records based on location, time, and hazard type to a named event, PDD, or GLIDE.

Because of inaccuracies in the spatial identification of hazard events within the NCEI’s Storm Data reports, there are instances in SHELDUS™ where inland counties will contain property and/or crop losses from coastal hazard events. This issue mainly occurs when an event is labeled as a "statewide" event by the NCEI in which each county receives an equal percentage of losses irrespective of spatial location or hazard event type. Hence, a hazard event identified as "flooding, winter weather, coastal storm" that is given a statewide locational identifier is treated as an event that impacted each county equally. Therefore, inland counties may at times be attributed to events and losses that seem incapable of occurring.

Hazards such as high tide, tidal wave, rouge tide, beach erosion, high seas, heavy surf, etc. are classified as coastal hazards. For more information see Coastal Event Types.

The Federal Information Processing Standard (FIPS) provides the names and codes that represent each of the unique counties and/or other equivalent legal/statistical subdivisions of the 50 States, the District of Columbia, and the possessions and freely associated areas of the United States. The last three digits of the FIPS code refer to the county, whereas the preceding one or two digits identify the state. Changes in FIPS codes are published by the National Institute of Standards and Technology (NIST) after approval by the Secretary of Commerce. Questions concerning the list of entities and their assigned codes are to be addressed to the Maintenance Agency: Office of the Chief, Geography Division, Bureau of the Census, Washington, D.C. 20233. For information on changes to FIPS codes and county names, see U.S. Census Substantial Changes to Counties and County Equivalent Entities: 1970-Present or go to the metadata.

The GLIDE number is an internationally recognized global identifier for large-scale events. GLIDE numbers are issued by members of the GLIDE initiative and upon request. SHELDUS™ does not include all U.S.-related GLIDE numbers, nor is there a GLIDE number for every large-scale U.S. event. SHELDUS™ includes only GLIDE numbers for selected major events, given a GLIDE number exists for said events. For more information see the GLIDE website.

A presidential disaster declaration (PDD) is a FEMA-issued number for disaster declarations by each state that is approved by the President, authorizing federal assistance in a state's disaster response. For every state, FEMA lists so-called designated counties affected by the event. SHELDUS™ does not include every PDD issued by FEMA. SHELDUS™ includes only PDDs for selected major events. For more information see presidential disaster declarations.

The Integrated Research on Disaster Risk (IRDR) program developed the peril classification system to help standardize losses databases. A peril is a hazard event that can be classified into one of six categories: Geophysical, Hydrological, Meteorological, Climatological, Biological, or Extraterrestrial. For more information see IRDR Peril Classification and Hazard Glossary.

Hazard days are days in which a loss (property, crop, injury, or fatality) occurred from a hazard. A count of hazard days will only be returned when data is aggregated.

There are many records in SHELDUS™ where the loss was caused by multiple hazards (e.g., Wind and Hail). The aggregation algorithm splits the losses equally between all involved hazard types. This can lead to the reporting of hazard types that were not originally part of your search. We recommend either ignoring those hazards or assigning them to another hazard type that was part of your query.

Landslide loss estimates were primarily gathered from the 2015 NWSI 10-1605 Storm Data. If there was no basis for the loss amount, $99 was entered as the property loss. See Metadata for details.

Social vulnerability data and metrics can be found at VMAP

When a university/organization that you belong to holds a subscription, the following information will be displayed on top of the page that displays once you logged into SHELDUS:

"[Name of organization] holds a subscription to SHELDUS."