High Point
Population 120,571 (2025)
15 tropical storms and hurricanes have passed within 50 miles of High Point since 1851; the strongest at closest approach was an unnamed storm in 1896 (Category 1).
Hazard fingerprint Each spoke is this county’s percentile among U.S. counties where that hazard occurs. How it is computed
- Tornado damage paths within 25 miles since 195056
- Tropical cyclone tracks within 100 miles since 1851, wider where stronger32
- Major flood years since 1978, Guilford County7
At a glance
Tornado paths within 25 miles, tropical cyclone tracks within 100 miles and wildfire perimeters within 25 miles of the city centre. Storm events, flood insurance claims and disaster declarations are for Guilford County. Earthquakes within 50 miles, volcanoes within 100 miles and smoke days are measured from the city centre; river and tide gauges, tsunami and landslide records and the drought index are for Guilford County.
Strongest tornado
F3
May 5, 1989, 10.5 mile path
Strongest tropical cyclone
Cat. 1
Hurricane (unnamed), 1896, 48.7 miles away
Tornadoes
About one every 1.4 years since 1950, 5 of them rated F3/EF3 or stronger.
Strongest
May 5, 1989
F3, 10.5 mile path
200 yards wide.
Deadliest
November 16, 2011
2 killed, EF2
15 injured along the whole path.
Most recent
Thursday, March 18, 2021
EF1, 2.6 mile path
5 years ago.
Every recorded tornado
| Mar 18, 2021 | EF1 | 2.6 | 0 | 0 |
| Feb 6, 2020 | EF1 | 0.4 | 0 | 0 |
| Apr 15, 2018 | EF2 | 32.8 | 5 | 0 |
| Feb 3, 2016 | EF1 | 1.7 | 0 | 0 |
| Feb 3, 2016 | EF0 | 1.0 | 0 | 0 |
| Nov 16, 2011 | EF2 | 12.5 | 15 | 2 |
| Mar 28, 2010 | EF3 | 3.5 | 0 | 0 |
| Mar 28, 2010 | EF1 | 0.8 | 0 | 0 |
| Aug 27, 2008 | EF0 | 0.5 | 0 | 0 |
| May 8, 2008 | EF2 | 3.9 | 3 | 1 |
| May 8, 2008 | EF3 | 2.9 | 2 | 0 |
| May 8, 2008 | EF2 | 0.3 | 0 | 0 |
| May 8, 2008 | EF2 | 3.2 | 0 | 0 |
| Sep 14, 2007 | EF0 | 0.1 | 0 | 0 |
| Sep 14, 2007 | EF0 | 0.1 | 0 | 0 |
| Sep 14, 2007 | EF0 | 0.2 | 0 | 0 |
| Jul 7, 2005 | F0 | 5.0 | 0 | 0 |
| Jul 7, 2005 | F0 | 8.0 | 0 | 0 |
| Sep 17, 2004 | F1 | 15.3 | 0 | 0 |
| May 7, 1998 | F1 | 1.0 | 0 | 0 |
| May 7, 1998 | F1 | 1.5 | 0 | 0 |
| May 7, 1998 | F1 | 0.1 | 0 | 0 |
| May 7, 1998 | F3 | 2.0 | 5 | 0 |
| May 7, 1998 | F0 | 5.0 | 0 | 0 |
| Mar 20, 1998 | F1 | 1.5 | 3 | 0 |
| May 6, 1996 | F1 | 0.1 | 0 | 0 |
| Mar 29, 1991 | F2 | 28.0 | 0 | 0 |
| Jun 16, 1989 | F1 | 0.5 | 0 | 0 |
| May 5, 1989 | F2 | 5.5 | 10 | 0 |
| May 5, 1989 | F3 | 10.5 | 30 | 0 |
| May 5, 1989 | F2 | 0.5 | 8 | 0 |
| May 22, 1985 | F3 | 3.5 | 0 | 0 |
| Jul 22, 1983 | F1 | 0.1 | 0 | 0 |
| May 26, 1983 | F1 | 0.1 | 0 | 0 |
| Mar 8, 1983 | F0 | 0.1 | 0 | 0 |
| Jun 3, 1982 | F0 | 0.1 | 0 | 0 |
| Jun 6, 1981 | F2 | 9.4 | 1 | 0 |
| Apr 9, 1980 | F1 | 1.9 | 0 | 0 |
| Oct 1, 1977 | F2 | 9.4 | 0 | 0 |
| Oct 8, 1976 | F1 | 0.7 | 0 | 0 |
| Oct 8, 1976 | F1 | 0.5 | 0 | 0 |
| Mar 24, 1975 | F1 | 7.1 | 1 | 0 |
| Jun 17, 1973 | F1 | 0.1 | 2 | 0 |
| May 28, 1973 | F1 | 4.0 | 0 | 0 |
| May 28, 1973 | F0 | 0.1 | 2 | 0 |
| Aug 18, 1970 | F1 | 0.1 | 0 | 0 |
| Apr 18, 1969 | F2 | 0.1 | 1 | 0 |
| Apr 17, 1967 | F1 | 2.0 | 0 | 0 |
| Jun 12, 1962 | F1 | 1.0 | 0 | 0 |
| May 11, 1961 | F0 | 0.5 | 0 | 0 |
| Mar 30, 1960 | F1 | 56.2 | 0 | 0 |
| Sep 29, 1959 | F1 | 0.1 | 0 | 0 |
| Jul 29, 1958 | F0 | 0.1 | 0 | 0 |
| Apr 5, 1957 | F1 | 4.7 | 1 | 0 |
| Jun 16, 1954 | F2 | 6.1 | 1 | 0 |
| Aug 31, 1952 | F1 | 0.1 | 0 | 0 |
- Injuries and deaths are for the tornado’s whole path, which may extend beyond this area.
- Weak tornadoes were under-recorded before Doppler radar coverage became national in the early 1990s, so earlier decades read low. Ratings use the Fujita scale before February 2007 and the Enhanced Fujita scale after.
Storm Prediction Center severe weather database, 1950 to 2025.
Hurricanes and tropical storms
15 passed within 50 miles since 1851; 1 at hurricane strength.
Strongest within 50 miles
September 30, 1896
Unnamed storm, Category 1
48.7 miles at closest approach, winds near 81 mph.
Most recent
July 8, 2021
Elsa, Tropical storm
64.3 miles at closest approach.
Every storm within 100 miles
| Elsa | 2021 | 64.3 | Tropical storm |
| Claudette | 2021 | 83.5 | Tropical storm |
| Zeta | 2020 | 63.6 | Tropical storm |
| Nestor | 2019 | 79.4 | Post-tropical |
| Michael | 2018 | 26.8 | Tropical storm |
| Andrea | 2013 | 95.4 | Post-tropical |
| Alberto | 2006 | 90.6 | Post-tropical |
| Fran | 1996 | 62.7 | Tropical storm |
| Hugo | 1989 | 89.3 | Tropical storm |
| Bob | 1985 | 13.5 | Tropical storm |
| David | 1979 | 10.7 | Tropical storm |
| Alma | 1970 | 67.6 | Tropical storm |
| Unnamed | 1965 | 84.9 | Post-tropical |
| Gracie | 1959 | 88.2 | Tropical storm |
| Diane | 1955 | 77.3 | Tropical storm |
| Hazel | 1954 | 94.6 | Post-tropical |
| Able | 1952 | 14.4 | Tropical storm |
| Unnamed | 1949 | 44.1 | Tropical storm |
| Unnamed | 1945 | 47.3 | Tropical storm |
| Unnamed | 1944 | 69.1 | Post-tropical |
| Unnamed | 1935 | 71.2 | Tropical storm |
| Unnamed | 1929 | 56.0 | Post-tropical |
| Unnamed | 1915 | 20.4 | Tropical storm |
| Unnamed | 1912 | 86.8 | Post-tropical |
| Unnamed | 1904 | 82.1 | Tropical storm |
| Unnamed | 1902 | 40.0 | Post-tropical |
| Unnamed | 1902 | 56.0 | Tropical storm |
| Unnamed | 1899 | 85.4 | Tropical storm |
| Unnamed | 1896 | 48.7 | Category 1 |
| Unnamed | 1893 | 86.7 | Category 1 |
| Unnamed | 1893 | 96.0 | Tropical storm |
| Unnamed | 1893 | 8.2 | Tropical storm |
| Unnamed | 1889 | 34.1 | Tropical storm |
| Unnamed | 1888 | 56.0 | Tropical storm |
| Unnamed | 1886 | 85.3 | Tropical storm |
| Unnamed | 1886 | 8.1 | Tropical storm |
| Unnamed | 1885 | 40.0 | Tropical storm |
| Unnamed | 1882 | 15.6 | Tropical storm |
| Unnamed | 1878 | 10.2 | Tropical storm |
| Unnamed | 1877 | 73.4 | Post-tropical |
| Unnamed | 1867 | 75.0 | Tropical storm |
| Unnamed | 1859 | 25.4 | Tropical storm |
| Unnamed | 1854 | 84.9 | Tropical storm |
- Tropical storms and hurricanes (34 kt or more, still tropical) at closest approach. Post-tropical remnants with gale-force winds are listed but not counted. Direct: track within 50 miles; near: within 100 miles. Distance is measured to the county boundary for counties and to the city centre for cities, using positions interpolated hourly between HURDAT2 fixes.
National Hurricane Center HURDAT2, 1851 to 2025.
Wildfire and smoke
No large wildfire has been mapped within 25 miles since satellite mapping began in 1984.
Smoke overhead
Smokiest year
2023: 40 days
Heavy smoke on 5 days in 2021, the most of any year.
Last 10 years
9.2 days a year
Medium or heavy smoke, 2016 to 2025.
2025
8 days
Medium or heavy smoke. 25 so far in 2026.
- A smoke day is a date on which a smoke plume traced by NOAA Hazard Mapping System analysts from satellite imagery covered this place's point (the county's population centre or the city centre). Counts here are of medium or heavy smoke. Since 2018 analysts have often drawn light smoke as one area over most of the continent, so light-smoke counts are not comparable from year to year. The plumes show smoke anywhere in the air above, not air quality at the ground, and smoke hidden by cloud is missed.
NOAA Hazard Mapping System smoke analysis, 2011 to 2026, retrieved October 30, 2026.
Floods and flood insurance
680 federal flood insurance claims since 1978, with $9.4 million paid.
Flood insurance figures are for Guilford County, the county that contains High Point.
Most claims in one year
1979: 75 claims
$730,000 paid.
2nd most
2000: 62 claims
$1.4 million paid.
3rd most
2003: 61 claims
$763,000 paid.
Claims by ZIP code
| 27407 | 192 | $4.1 million |
| 27408 | 130 | $2.1 million |
| 27262 | 46 | $379,000 |
| 27405 | 46 | $474,000 |
| 27406 | 45 | $454,000 |
| 27403 | 37 | $230,000 |
| 27410 | 35 | $454,000 |
| 27265 | 35 | $146,000 |
| 27401 | 21 | $286,000 |
| 27260 | 15 | $44,000 |
| 27420 | 14 | $106,000 |
| 27249 | 11 | $99,000 |
| 27429 | 8 | $44,000 |
| 27409 | 6 | $75,000 |
| 27263 | 5 | $17,000 |
| 27455 | 5 | $1,601 |
Flood events since 1996
- Flash Flood137
- Flood5
- Heavy Rain1
1 death recorded in flood events since 1996.
This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026. NOAA Storm Events through 2026.
River crests
River gauges in Guilford County, the county that contains High Point.
Most severe crest
September 22, 1979
North Buffalo Creek at Greensboro, 20.12 ft
7.12 feet above the 13.0 ft flood stage; major flooding by today’s categories.
Most recent moderate or major crest
August 10, 2024
South Buffalo Creek near Pomona, 14.46 ft
Moderate flooding.
River gauges
| Brush Creek at Muirfield Rd in Greensboro | 9.0 | 11.08 ft | 0 |
| East Fork of Deep River near High Point | 10.0 | 15.44 ft | 0 |
| Horsepen Creek at US-220 Near Greensboro | 11.0 | 11.94 ft | 0 |
| North Buffalo Creek at Church St in Greensboro | 14.0 | 18.96 ft | 1 |
| North Buffalo Creek at Greensboro | 13.0 | 20.12 ft | 1 |
| North Buffalo Creek at SR2819 near McCleansville | 17.0 | 21.45 ft | 0 |
| North Buffalo Creek at Westover Terrace | 10.0 | 14.07 ft | 0 |
| Reedy Creek at NC2128 Nr Oak Ridge | 10.0 | 15.06 ft | 1 |
| Reedy Creek near Gibsonville | 12.0 | 18.51 ft | 0 |
| Ryan Creek below US220 at Greensboro | 8.0 | 12.53 ft | 0 |
| South Buffalo Creek at McConnell Rd Nr Greensboro | 17.0 | 14.64 ft | 0 |
| South Buffalo Creek at US220 Nr Greensboro | 18.0 | 16.77 ft | 0 |
| South Buffalo Creek near Pomona | 11.0 | 15.47 ft | 0 |
- Crests are the highest and the recent crests the National Weather Service lists for each river gauge in the county that has a flood stage, not every flood. Flood categories use each gauge's current flood stages; crests from before levees, dams or channel changes may not be comparable. Crests measured on an old datum are left out of the rankings.
NOAA National Water Prediction Service gauge records, retrieved October 30, 2026.
Drought
In severe drought or worse for 88 of 1,581 months since 1895 (6%); the longest spell lasted 11 months.
The drought index is for Guilford County, the county that contains High Point.
88
Months in severe drought or worse since 1895
35
Months in extreme drought
6%
Share of all months, severe or worse
Lowest reading
July 2002
−5.66, extreme drought
Longest severe spell
11 months
October 2001 to August 2002.
Latest month
September 2026
−4.77, extreme drought
- The Palmer Drought Severity Index is computed by NOAA each month from the county's average temperature and precipitation, relative to the county's own climate. Zero is normal; -3 or lower is severe drought and -4 or lower extreme drought. It describes the long-term balance of moisture, not water supply or crop losses.
NOAA NCEI nClimDiv county Palmer Drought Severity Index, 1895 to September 2026, issued October 6, 2026.
Earthquakes
8 earthquakes of magnitude 2.5 or more within 50 miles since 1980; none reached magnitude 4.
0
Magnitude 3+ within 50 miles since 1973
0
Magnitude 4+ within 50 miles since 1900
0
Magnitude 5+ within 50 miles since 1900
Largest within 50 miles
March 4, 1981
Magnitude 2.8
6 km E of Randleman, North Carolina; 19.0 miles away, 0.6 miles deep.
- Earthquakes of magnitude 2.5 or more in the USGS Comprehensive Catalog since 1900. Within 50 miles means the epicentre lies within 50 miles of the city centre.
- Small earthquakes were under-recorded before the modern seismic networks of the 1970s and are still missed in remote areas, so early decades read low. Magnitudes are as the catalogue reports them and mix scales (moment, local and body-wave).
USGS ANSS Comprehensive Earthquake Catalog, 1900 to present, retrieved October 30, 2026.
Severe weather and other events
926 events in the National Weather Service record for Guilford County, 803 of them since 1996.
113
Hail reports, 1 inch or larger
6
Hail, 2 inches or larger
361
Damaging gusts, 58 mph+
86
Winter weather events since 1996
4
Heat events since 1996
2
Cold events since 1996
Largest hail
April 2, 1983
2.75 inches
Strongest measured or estimated gust
July 15, 1976
97 mph
More event types since 1996
| Lightning | 9 | 0 |
Costliest events since 1996
- Apr 15, 2018Tornado$65.0 million
National Weather Service narrative
The tornado initially touched down on the north side of I-40 near |where Willow Road crosses I-40. Damage at this point consisted of |snapped trees and was consistent with 90 mph wind speeds, or EF-1 on |the Enhanced Fujita Scale. | |The tornado remained on the ground as it traveled north toward |Peeler Elementary School. Numerous homes in this area were damaged |along with substantial tree damage. The tornado wind speeds at this |location were estimated to be approximately 100 mph. | |The tornado continued traveling north and reached a peak intensity |and maximum path width in the Hampton Community and near Hampton |Elementary School. At this school a large portion of the roof…
- Sep 17, 2018Flood$14.6 million
National Weather Service narrative
Torrential rainfall of 6 to 8 inches caused widespread flooding across the county, which caused moderate flooding along North Buffalo and South Buffalo Creeks, as well as other creeks and streams throughout the county. Flooding damaged approximately 119 structures throughout the county, destroying 7 and resulting in over $14.63 million in property damage. Numerous roads were closed due to flooding. Numerous homes and businesses were flooded as well. While final losses on crops are not yet tallied, estimates around $5 million or more are possible.
- Mar 28, 2010Tornado$10.0 million
National Weather Service narrative
The tornado initially touched down as an EF1 with winds around 100 mph near Old Plank Road in southwest Guilford County. It was in this area where the Apple Tree Academy sustained significant damage and two vehicles including a small bus were|rolled 50 yards across the street. From this point the tornado continued northeast|across Highway 311. ||The next area to experience damage was just north of Highway 311 and south of Old Mill Road along Langdale, Imperial and Impala Drives. Tornado damage in this area continued to indicate EF1 winds with numerous trees down along with a number of home with roof and siding damage. The tornado intensified to an EF2 as it crossed Old Mill Road…
- Mar 6, 2014Ice Storm, Guilford$8.1 million
National Weather Service narrative
One quarter to one half of an inch of ice from freezing rain resulted in widespread downed trees and power-lines. Additionally, snowfall of 4 to 7 inches fell across northern portions of the county.
- May 8, 2008Tornado$4.0 million
National Weather Service narrative
The tornado, originally an EF-0, initially touched down just north of Squire Davis Park near the intersection of Sandy Ridge Road and Johnson Street. From there the tornado tracked northeast and intensified to EF-1 intensity as it approached the Farmers Market and Interstate 40. The tornado overturned several cars and tractor trailers as it crossed Interstate 40. A roof was blown off of an office building just north of the interstate as the tornado continued to intensify.||As the tornado moved further northeast into an industrial complex, it further strengthened to EF-2 with winds estimated around 130 mph based on damage to warehouses. Numerous warehouses along Little Santee Road,…
- Jun 3, 2009Flash Flood$2.0 million
National Weather Service narrative
Numerous streets were closed in downtown Greensboro with as many as 50 to 100 water rescues performed, mainly from stalled out vehicles. Multiple buildings were flooded, with at least 10 to 15 on the UNC-Greenbsoro Campus alone. In addition, as many as two dozen businesses and government buildings were also flooded. One fatality occurred when a woman lost control of a moped and went into a creek. A police officer rescued the woman, only to have her jump back into the creek in an attempt to recover her moped.
- Jun 12, 2010Lightning$1.5 million
National Weather Service narrative
Lightning struck a large fuel tank at the Colonial Pipeline gasoline tank farm resulting in a large fire destroying the tank and resulting in the closure of Interstate 40 for four hours. The tank contained 840,000 gallons of gasoline at the time of the fire.
- Oct 11, 2018Tropical Storm, Guilford$1.5 million
National Weather Service narrative
Tropical storm wind gusts caused significant damage to homes and other structures across the county. A total of 321 homes were damaged from fallen trees, with seven destroyed, 88 being classified as having major damage, 121 seeing minor damage and the rest listed as ���affected.��� At the peak of the storm, the total peak outages were around 130,000 customers.
- Oct 29, 2020Tropical Storm, Guilford$1.5 million
National Weather Service narrative
Frequent wind gusts of 40 to 55 mph resulted in scattered to numerous trees and power lines down across Guilford County, including some on homes. Numerous customers lost power in Guilford County as a result of the tropical storm force winds.
- Feb 25, 2011Strong Wind, Guilford$1.0 million
National Weather Service narrative
Strong winds with gusts to 45-50 mph in the Triad resulted in a number of power outages and downed trees.
- Storm Events records before 1996 cover only tornadoes, thunderstorm wind and hail. Damage figures are as reported by the National Weather Service at the time, not adjusted for inflation.
NOAA NCEI Storm Events Database, 1950 to 2026, issued October 26, 2026.
Weather records
From Greensboro Airport, 7.8 miles from the city centre, with records from 1928.
- All-time high
- 103°FAug 18, 1988
- All-time low
- −8°FJan 21, 1985
- Warmest night
- 80°FAug 9, 2007
- Coldest day
- 13°FJan 30, 1966
- Wettest day
- 7.46 inSep 24, 1947
- Snowiest day
- 14.3 inDec 17, 1930
- Hottest year
- 2007mean 61.5°F
- Coldest year
- 1963mean 56.2°F
- Wettest year
- 201864.11 in
- Driest year
- 194127.74 in
- Snowiest season
- 31.7 in1959-60
Median first snow
December 29
Earliest: November 9, 1968
Median last snow
February 22
Latest: March 30, 2003
7 of 97 winters had no measurable snow.
Station Greensboro Airport (USW00013723), 902 ft elevation, 7.8 miles from the city centre. Daily records from 1928 to October 27, 2026; 100.0% of days in the last 30 years are complete. Records at a single station can differ from a city’s official threaded record, which may combine several stations.
NOAA NCEI Global Historical Climatology Network Daily.
Federal disaster declarations
28 since 1953. The most recent: Severe Winter Storm, January 24, 2026.
Declarations for Guilford County.
| Jan 24, 2026 | Winter Storm | EM-3637-NC |
| Sep 26, 2024 | Tropical Storm | EM-3617-NC |
| Aug 6, 2024 | Tropical Storm | EM-3608-NC |
| Oct 1, 2022 | Hurricane | EM-3586-NC |
| Aug 2, 2020 | Hurricane | EM-3534-NC |
| Mar 25, 2020 | Biological | DR-4487-NC |
| Mar 13, 2020 | Biological | EM-3471-NC |
| Sep 3, 2019 | Hurricane | EM-3423-NC |
| Sep 14, 2018 | Hurricane | DR-4393-NC |
| Sep 10, 2018 | Hurricane | EM-3401-NC |
| May 8, 2018 | Severe Storm | DR-4364-NC |
| Oct 7, 2016 | Hurricane | EM-3380-NC |
| Mar 31, 2014 | Severe Ice Storm | DR-4167-NC |
| Sep 5, 2005 | Hurricane | EM-3222-NC |
| Sep 18, 2004 | Hurricane | DR-1553-NC |
| Mar 27, 2003 | Severe Ice Storm | DR-1457-NC |
| Dec 12, 2002 | Severe Ice Storm | DR-1448-NC |
| Jan 31, 2000 | Severe Storm | DR-1312-NC |
| Sep 16, 1999 | Hurricane | DR-1292-NC |
| Sep 15, 1999 | Hurricane | EM-3146-NC |
| Sep 6, 1996 | Hurricane | DR-1134-NC |
| Feb 23, 1996 | Snowstorm | DR-1103-NC |
| Jan 13, 1996 | Snowstorm | DR-1087-NC |
| Mar 17, 1993 | Snowstorm | EM-3110-NC |
| Sep 25, 1989 | Hurricane | DR-844-NC |
| May 17, 1989 | Tornado | DR-827-NC |
| Aug 11, 1977 | Drought | EM-3049-NC |
| Mar 2, 1977 | Snowstorm | EM-3033-NC |
This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
OpenFEMA Disaster Declarations Summaries, retrieved October 30, 2026. Statewide declarations are not listed.
Sources and vintage
Every number on this page comes from these public records.
- Tornadoes NOAA Storm Prediction Center severe weather database, through 2025.
- Tropical cyclones NOAA National Hurricane Center HURDAT2 (Atlantic; Northeast and Central Pacific), through 2025.
- Wildfire USGS/USFS Monitoring Trends in Burn Severity, through 2026.
- Storm events NOAA NCEI Storm Events Database, through 2026.
- Flood insurance OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026.
- Declarations OpenFEMA Disaster Declarations Summaries v2, retrieved October 30, 2026.
- Weather records NOAA NCEI Global Historical Climatology Network Daily, station USW00013723.
- River crests NOAA National Weather Service, National Water Prediction Service river gauges, retrieved October 30, 2026.
- Drought NOAA NCEI nClimDiv county Palmer Drought Severity Index, through September 2026.
- Smoke NOAA NESDIS Hazard Mapping System smoke analysis, retrieved October 30, 2026.
- Earthquakes USGS ANSS Comprehensive Earthquake Catalog (ComCat), retrieved October 30, 2026.
Joins, thresholds and known limits are set out in the methodology. Found an error? Report it. Page built October 30, 2026.