HMS-Smoke

June 11, 2026 · View on GitHub

NOAA's Hazard Mapping System (HMS)

The HMS Smoke Explorer allows end-users to visualize NOAA's Hazard Mapping System (HMS) smoke and fire products, MODIS aerosol optical depth, and GOES-East/West RGB imagery. Since 2005, NOAA analysts have been inspecting satellite imagery (e.g. GOES, MODIS, VIIRS) and manually outlining the extent of smoke across North America, classified into three density categories: light, medium, and heavy, to produce the HMS smoke product. A corresponding HMS fire product includes active fire detections from multiple satellites/sensors (e.g., MODIS, VIIRS, GOES, AVHRR) with quality control by the analysts.

The latest date available in the HMS Smoke Explorer on Google Earth Engine (GEE) is June 8, 2026.

banner image

Tool Capabilities

  • Make an animation looping GOES-East/West RGB imagery. Right-click on the GIF and select "Save Image As..." to save the animation to your local storage.
  • View satellite-derived (MODIS) and model forecast (CAMS) aerosol optical depth and surface PM2.5 with HMS smoke.
  • View HMS smoke text descriptions and summary statistics.

Datasets on HMS Smoke Explorer

The HMS Smoke Explorer covers the time range of the HMS Smoke Product (2005/08-present). Ancillary datasets for visualization are listed below.

DatasetTime RangeSpatial Resolution
HMS Smoke2005/08-present--
HMS Fire2003/04-present--
HMS Smoke Text2005/07-present--
MODIS Burned Area2000/10-present500 m
MODIS MAIAC Aerosol Optical Depth (AOD)2000/02-present1 km
ECMWF/CAMS AOD, PM2.52016/06-present0.4°
GOES-16/East2017/07-2025/042 km
GOES-17/West2018/12-2023/012 km
GOES-18/West2022/10-present2 km
GOES-19/East2025/04-present2 km

HMS on Google Earth Engine

The processed HMS smoke product can be used for analysis on Google Earth Engine and downloaded as yearly files. Note that 2005-2010 includes gap-filled smoke densities (fillFlag > 0).

// read HMS smoke polygons and active fires by year
var inYear = 2020;
var HMS = ee.FeatureCollection('projects/GlobalFires/HMS/Smoke_Polygons/HMS_' + inYear);
var HMS_Fire = ee.FeatureCollection('projects/GlobalFires/HMS/Fire_Points/HMS_Fire_' + inYear);

// filter by month and day
var inMonth = 8;
var inDay = 1;
var HMS_day = HMS.filter(ee.Filter.eq('Month',8)).filter(ee.Filter.eq('Day',1));
var HMSFire_day = HMS_Fire.filter(ee.Filter.eq('Month',8)).filter(ee.Filter.eq('Day',1));

Map.addLayer(HMS_day);
Map.addLayer(HMSFire_day, {color:'red'});
Map.centerObject(HMS_day);

print(HMS_day);
print(HMSFire_day);

HMS Smoke Product

VariableDescriptionFormat
IDUnique ID for each polygonYYYYJJJ (1-4 = year, 5-7 = day of year, 8-11 = original row of a polygon in that day's raw HMS file)
YearYear2005-present
MonthMonth1-12
DayDay1-31
JDayJulian day or DOY1-366
StartStart time, UTCHHMM
EndEnd time, UTCHHMM
StSecStart timeseconds since 1970-01-01
EndSecEnd timeseconds since 1970-01-01
DurationEnd time minus start time, with a 15-min bufferhours
DensityDensity of smoke polygon'Light', 'Medium', 'Heavy', or 'Unspecified'
SatelliteSatellite used as a reference for the polygone.g., 'GOES-EAST', 'GOES-WEST'
AreaArea of polygonkm2
QAFlagQA flag0-5 (valid: 0 = good, 1 = coordinates adjusted, 2 = unclosed rings; invalid and not included in SHP: 3 = linestring, 4 = point / empty, 5 = crossed edges)
IsMultiIs the polygon a multipolygon?'Y' or 'N'
fillFlag*Flag on gap-filling smoke density0 = no gapfill, 1 = gapfill (model with AOD), 2 = gapfill (model without AOD)
fillConf*Confidence on gap-filled density based on predicted model outcomes from bootstrapping (polygons that did not need gap-filling are automatically labeled with a value of 1)0-1

* only relevant for 2005-2010, so HMS files for only those years have these columns on GEE

Notes:

  • The start and end time represent the time bounds of the satellite images used to draw the HMS polygons, not the actual persistence duration of the smoke plume
  • In the tool, duration is used to estimate the annual contribution of each smoke density category at a particular location
  • For QA = 1, out-of-bounds coordinates with y > 90 or y < -90 are removed (removes some anomalous coordinates), x < -180 is forced to be x = -180 as this may lead to disfigured polygons on GEE
  • For QA = 2, the first coordinate is repeated at the end of the list of coordinates to close the polygon ring

Caveats

  • The HMS smoke product represents smoke as seen from satellites. In some places, smoke may be aloft and may not affect surface air quality. This is particularly true for light smoke.
  • Use caution when assessing trends in smoke using the HMS smoke product outside of CONUS. Note the lower spatial coverage in earlier years, which can be seen from the artificial boundaries in annual aggregates.
  • The HMS 'Duration' is calculated from the start and end times of satellite images used to outline the smoke. Thus, it is not an estimate of the true smoke duration. The HMS smoke polygon represents the maximum extent of smoke during this duration.
  • HMS analysts outline smoke using only daytime satellite imagery. Smoke plumes are added throughout the day as new satellite imagery becomes available, though analysts generally analyze larger smoke plumes only twice per day in the morning and late afternoon.
  • HMS smoke polygons in 2005-2007, 2009, and some in 2008 and 2010 are not classified into smoke density classes (light, medium, heavy). We used random forest modeling to assign densities to all such polygons.
  • HMS smoke polygons with bad geometries and throws an error in R (i.e. drawn as lines rather than polygons, edges crossing edges) have been removed.
  • GOES-16/East became operational on December 18, 2017, GOES-17/West on February 12, 2019, GOES-18/West on January 4, 2023 (replacing GOES-17/West), and GOES-19/West on April 7, 2025 (replacing GOES-16/East). Note these dates when selecting the GOES RGB images.

Summary Stats and Quality Control

Number of HMS polygons in each year, and how many are invalid after processing in R. The number of smoke polygons with gapfilled densities are also shown below.

YearTotalValidInvalidGapfill
20056296629156291
20061545315448515448
20071988119876519618
20082320323190135074
200923517234952223347
20102724127223187440
2011337213371470
2012279722797020
20132316223149130
2014185651856140
20151635616346100
20162128021269110
2017258432584120
20184133141320110
20194294542934110
2020454404543820
2021275732757300
2022219062190600
2023203032030210
2024125441254220
2025241752417320
2026203262032600

Missing Dates

20050809,20050810,20060327,20060401,20060714,20060715,20061104,20070331,20070821,20080123,20080124,20080305,20081005,20090130,20090408,20121007,20150602,20150820,20160306,20161112,20170427,20170531,20170601,20170622,20170718,20190710,20190810

Caveats

  • The availability of the satellites is not uniform throughout the record. For example, recent years have higher-resolution active fire detections from VIIRS, which is more capable at detecting small fires.
  • The geolocation error for active fire detections varies among different satellites/sensors (e.g., 10s-100s m for VIIRS and up to 1 km for GOES) (see NOAA's HMS FAQ)
  • There are missing HMS fire data (no .zip files) on some days.
  • Some entries have malformed and/or missing date/time.

HMS Fire Product

VariableDescriptionFormat
LonLongitude (center) of active fire coordinatesfloat
LatLatitude (center) of active fire coordinatesfloat
YearYear (HMS filename)2003-present
MonthMonth (HMS filename)1-12
DayDay (HMS filename)1-31
JDayJulian day or DOY (HMS filename)1-365
YearSatYear (satellite)2003-present
MonthSatMonth (satellite)1-12
DaySatDay (satellite)1-31
JDaySatJulian day or DOY (satellite)1-365
HHMMSatHour/minute of active fire detection, UTCHHMM
SatelliteSatellite origin of active fire detectione.g., 'GOES-EAST', 'GOES-WEST'
MethodMethod of active fire detectionANALYSIS = manual input, other labels = automated
EcosystemEcosystem category derived from the Global Land Cover Characterization databaseinteger
QAFlagQA flag for satellite detection date/time0, 1 (valid: 0 = good, 1 = date/time invalid and filled with HMS filename)

Summary Stats and Quality Control

Number of HMS active fires from various satellites and missing days since April 1, 2003. MODIS includes Aqua and Terra, VIIRS includes S-NPP, NOAA-20, and NOAA-21, GOES includes GOES-East and GOES-West, and AVHRR includes NOAA-15 to NOAA-19 and METOP-A/B/2.

YearAvailable DaysTotal Active FiresMODISVIIRSGOESAVHRRUnspecifiedMalformed Datetime (%)
20032191922645666107842241818153630
2004362531036175776013487222038800
2005360651044228018019284723017900
200636028592110608007242310741800
200736331365610660205571615133800
200836648166617392708650722123200
20093632708339384304473313225700
201036533067812012706323714731400.02
20113655203651733930127661219238160.03
2012366433654144903010457018418100
20133654652821608320118188186195670.01
20143643592491378363437466414640600
2015363322907130829067129124938110
20163623269091069021413785019120814370.01
201736071270117705421027814845917691000
2018362165173813038744382599086386653100
2019362257982410178221437312939744033700
20203662493748966692044170352909000
2021365416642914289825974931426038000
202236535707478092018344991655328000
20233658196303050366093159694000
20243668434632047730623661570000
20253658040406050762452938782000
20261604394508011099553284553000

Missing Dates or Corrupt Files

20030501,20030502,20030503,20030504,20030505,20030506,20030507,20030508,20030509,20030510,20030511,20030512,20030513,20030514,20030515,20030516,20030517,20030518,20030519,20030520,20030521,20030522,20030523,20030524,20030525,20030526,20030527,20030528,20030529,20030530,20030531,20030601,20030602,20030603,20030604,20030605,20030606,20030607,20030608,20030609,20030610,20030611,20030612,20030613,20030614,20030615,20030711,20030731,20030830,20030831,20030905,20030907,20030914,20031102,20031210,20031215,20040225,20040402,20040624,20041209,20050511,20050624,20050626,20050703,20050706,20060327,20060401,20060714,20060715,20061104,20070331,20070821,20090130,20090408,20140705,20150602,20150820,20160306,20161108,20161112,20161209,20170427,20170531,20170601,20170622,20170718,20180501,20181220,20181230,20190225,20190709,20190710

The HMS annual bundle files can be used to backfill dates with corrupt zip files (ancill/HMS_Fire_fill.R):

20250508,20250511

Basic Code for Processing HMS Products

Folder Structure:

HMS/ 
	Fire_Points/
		2003/
		...
		2024/
		processed/
	HMS_Extent/
	Smoke_Polygons/
		2003/
		...
		2024/
		processed/
	Smoke_Text/

Steps:

  1. Download the HMS .zip files to HMS/Smoke_Polygons/ and HMS/Fire_Points/ using ancill/HMS_Download.R and ancill/HMS_Fire_Download.R. Unzip using ancill/HMS_Unzip.R and ancill/HMS_Fire_Unzip.R.
  2. Process HMS daily shapefiles and output yearly shapefiles to HMS/Smoke_Polygons/processed/ and HMS/Fire_Points/processed/ using HMS.R and HMS_Fire.R.
  3. Retrieve HMS smoke text description links as .txt and output as yearly .csv tables in HMS/Smoke_Text/ using ancill/HMS_TextLinksYr.R; combine the .csv files into a single file, HMS/Smoke_Text/HMS_SmokeText.csv, using ancill/HMS_TextLinks.R

Gap-filling Unspecified Densities

We used random forest classification to assign densities (light, medium, or heavy) to polygons with unspecified densities from 2005-2010. This procedure is described in Liu et al. (2024, IJWF). Note that the code has been updated to use sf instead of rgdal, and additional processing has been done to fix more bad geometries; more years are now used to train the models. The code workflow uses GEE to generate some input data for the random forest model (HMS_Stack.js,HMS_AOD.js). The rest of the workflow is in R with gapfill/RFmodel_prepare.R to output a CSV table of data for all HMS polygons from 2005-2025, gapfill/RFmodel_withAOD.R and gapfill/RFmodel_withoutAOD.R to run the random forest classification models, gapfill/RFmodel_export.R to output another CSV table now with the gap-filled densities, and finally gapfill/HMS_gapfill_shp.R to write new HMS files from 2005-2010 with the gap-filled densities and associated flags. The gap-filling method is computationally intensive and takes around 1 week to complete in GEE and R, largely due to computing AOD for each polygon in GEE.

Updates

  • April 2026: added outlines of HMS polygons as a map layer and added map view settings to the HMS Smoke Explorer
  • March 2026: fixed additional HMS smoke polygons with crossed edges, added ancill/HMS_Fire_fill.R for backfilling dates with corrupt daily files, added download option for HMS annual bundles in R scripts
  • June 2025: fixed text replacement bug in dates for HMS_TextLinksYr.R that omitted links for August reports; updated descriptions for smoke text description and smoke extent panels on the GEE app; fixed label in historical smoke timeseries and typo in equation of the GOES green band in the GEE app
  • May 2025: updated UI_HMS_Smoke.js with GOES-19/East imagery and active fires
  • April 2025: updated ancill/HMS_TextLinksYr.R using the NOAA OSPO archive; the FTP server used previously is no longer available
  • October 2024: fixed missing HMS fire points in 2007
  • August 2024: replaced FIRMS with the HMS fire product for the active fires layer on the app, update MODIS burned area layer from Collection 6 to 6.1
  • July 2024: added VIIRS active fires to app; there seems to be some issues with recent active fire images in the Earth Engine / FIRMS dataset
  • September 2023: uploaded gap-filled HMS polygons from 2005-2010 and added related code; added ancillary code for preprocessing; added note about evaluation of the HMS smoke product on the app
  • July 2023: updated R code to process HMS from rgdal to sf, code is now more inclusive of out-of-bounds polygons and attempts to fix some bad geometries (unclosed rings and out-of-bounds coordinates) but excludes polygons with crossed edges as sf cannot fix them; added QA flags; added jump to latest button
  • September 2020: added option to select GOES-East or GOES-West full disk imagery, added CAMS PM2.5 and AOD
  • August 2020: added visualization of GOES RGB imagery, HMS smoke days and 'duration'

Publications

Liu, T., F.M. Panday, M.C. Caine, M. Kelp, D.C. Pendergrass, L.J. Mickley, E.A. Ellicott, M.E. Marlier, R. Ahmadov, and E.P. James (2024). Is the smoke aloft? Caveats regarding the use of the Hazard Mapping System (HMS) smoke product as a proxy for surface smoke presence across the United States. Int. J. Wildland Fire, 33, WF23148. https://doi.org/10.1071/WF23148