LoamBehind the verdict
Over 4,000 data points go into every verdict: twelve days of hourly weather, radar rain totals, soil moisture at two depths, evaporation, and the soil, slope and shade of the ground itself. They come from NOAA, NASA, the USGS, the USDA, the National Park Service and the European weather models, alongside the open data below.
These sources supply the data for each estimate. Learn how Loam uses them on how it works.
Open-Meteo
Weather for every network: recent precipitation, temperature, humidity, wind, and the forecast ahead.
Weather data by Open-Meteo, used under CC BY 4.0Apple Weather
A second reading of recent rain. When Apple Weather or a second forecast model reports a storm the primary feed missed, the verdict is scored on the wetter reading. It only ever adds rain, never removes it.
Weather data provided by Apple Weather and other sources. The data provided by Apple has been modified: a Loam verdict is Loam's own model run on it, not Apple's forecast.NOAA Multi-Radar Multi-Sensor (MRMS)
Observed rain for US networks, from radar corrected against rain gauges. Each hour it replaces the weather model's estimate of rain that has already fallen, so a storm the model missed or overstated is scored on what the radar measured. The forecast still comes from the weather models.
US Government work, public domainUSDA Natural Resources Conservation Service
Soil survey data: the texture and drainage behavior of the ground under a trail. Different soils hold and drain water at different rates.
US Government work, public domainSoilGrids, ISRIC World Soil Information
Soil properties for networks outside US soil survey coverage, including the Canadian catalog.
SoilGrids by ISRIC World Soil Information, used under CC BY 4.0. Poggio et al., SoilGrids 2.0, SOIL 7, 217-240, 2021USDA Forest Service and the Multi-Resolution Land Characteristics Consortium
US tree canopy cover from the National Land Cover Database. Loam samples the terrain around a network's mapped location to estimate cover. This is an environmental input, not the percentage of every trail mile under trees.
US Government work, public domainUniversity of Maryland: Hansen Global Forest Change
Canopy for Canadian networks uses the 2000 to 2023 release. It describes tree cover in 2000 and recorded forest loss through 2023; it is not a current aerial survey. It does not capture later tree growth or every change in cover.
The US and Canadian products have different methods and dates. A comparison of their sampled values needs that context. Each dated report describes the sample it uses; its figures should not be read as a survey of all trails in a state or province.
Hansen et al., Global Forest Change, version 1.11. Data available under CC BY 4.0USGS and NASA elevation data
Elevation and slope for each network, served through OpenTopoData. Slope helps estimate how quickly water drains.
US Government work, public domainNational Park Service
Official alerts and closures for the parks that publish them. A current closure from the managing authority overrides the model.
US Government work, public domainBeing tested
These sources are under evaluation. They are compared against Loam's verdicts and do not change them yet.
Environment and Climate Change Canada
Weather station observations and gauge-adjusted rain analysis for Canadian networks, checked against the model before they are used in a verdict.
Contains information licensed under the Open Government Licence, CanadaEnvironment Agency and the Scottish Environment Protection Agency
Rain gauge readings for a pilot that tests Loam's model on trail centres in England and Scotland. Loam is not available in the UK.
Contains public sector information licensed under the Open Government Licence v3.0Maps and trail names
OpenStreetMap contributors
Trail names and trail geometry, alongside published agency trail data.
Map data © OpenStreetMap contributors, available under the Open Database LicenseLoam Desk
Loam Desk is the byline for Loam's guides and reports. Ryan McLaughlin, Loam's creator and a mountain biker, is responsible for the articles. The guides explain how to use weather and terrain information when planning a ride. The reports describe Loam's environmental data and model results.
Sources are linked so readers can check the advice and figures. A source explaining soil or weather does not establish the accuracy of Loam's model. Reports identify their study dates and distinguish modeled results from observations on the trail.
For a correction, email [email protected] with the article URL, the detail to check, and a source if you have one. Substantive revisions carry an updated date. Original dated datasets remain identified by their study date.
Loam is independent
Loam is not affiliated with, endorsed by, certified by, or partnered with any organization named on this page. Their data is public, and Loam uses it under the terms listed above. Naming them here is credit, not a claim of approval.
Agency names identify our sources; they do not imply an endorsement.
The verdict itself is a modeled estimate, not an official trail status. Check the trail, and respect posted closures and local guidance.
Something look wrong?
Know a network whose soil, tree cover, or terrain looks wrong here? Tell us what you found. Email [email protected], or use the feedback controls in the app.