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Loam field report

State of the Dirt: 2025 in review

We took the weather from 2025 and asked a simple question: what would today's Loam model have told riders each day?

What Loam would have shown

We checked 24 riding areas once a day for all 365 days. That gave us 8,760 checks. Loam would have shown Prime on 6,327 of them and Dusty on 1,049. The rest were Caution, Stay off, or Frozen.

12.0%of checks were Dusty
72.2%of checks were Prime
2.9%of checks were Caution
6.2%of checks were Stay off
6.8%of checks were Frozen

What these numbers are

This is a replay made from old weather, not a diary written by people at the trail. It shows what Loam would have said. It does not prove what the dirt felt like or whether a trail was open.

The Southwest was often too dry

Loam uses Dusty when the ground has drained but the surface has dried past the Prime range. It is the tan state in the app, labeled Rideable, very dry.

Most of those days came from the Southwest. Phoenix Mountains Preserve in Arizona had 284 Dusty days. Gooseberry Mesa in Utah had 213, and the Montrose/Uncompahgre area in Colorado had 134. Together, those three places made up 60 percent of all Dusty results in the report.

Dusty days were most common in midsummer. We counted 197 in July and 183 in August. A trail could be dry enough to ride without having the moisture that makes dirt feel firm and grippy.

Winter belonged to Quebec and New Brunswick

The strongest winter pattern came from eastern Canada. Mont-Sainte-Anne in Quebec had 110 Frozen days. Bromont, also in Quebec, had 85. Crabbe Mountain in New Brunswick had 82.

January and February accounted for 354 of the year's 592 Frozen results. Loam marks snow-covered ground as Frozen, even when there has not been much rain.

Oregon and Ohio had the most Stay off days

Mt. Hood in Oregon had 77 Stay off days, the most in the report. Caesar Creek in Ohio had 65. Bear Mountain Bike Park in British Columbia had 52, and Hardesty Portal in Oregon had 47.

Loam judged that enough water remained in the ground at those places for riding to damage the trail.

Colorado had a different pattern. Montrose/Uncompahgre, Colorado, had 231 Prime days and 134 Dusty days, with no Caution, Stay off, or Frozen days. These numbers tell us how the model behaves, not what riders found on the trail. Today's model sees that area as draining very quickly, and we should compare that result with real trail reports.

All 24 riding areas

Each line covers one place for one year, so the five numbers add up to 365. We included the state or province and grouped nearby parts of the country together.

Riding areaDustyPrimeCautionStay offFrozen
Pacific Coast
Bear Mountain Bike Park, British Columbia030013520
Hardesty Portal, Oregon030113474
Mount Diablo, California882508190
Mt. Hood, Oregon57186237722
Southwest and Rockies
Gooseberry Mesa, Utah213146420
Brian Head Resort, Utah512773232
Phoenix Mountains Preserve, Arizona28477220
Mill Creek Pipeline, Utah8524181021
Munds Park, Arizona732731252
Montrose/Uncompahgre, Colorado134231000
Upper Midwest
Bertram Chain of Lakes Regional Park, Minnesota32276161229
Redhead Mountain Bike Park, Minnesota02912864
Olson Park, Michigan033161810
Midwest and Southeast
Caesar Creek, Ohio427413659
Athens Academy Trails, Georgia031617320
Withlacoochee State Forest, Florida633811100
Tannery Knobs, Tennessee03416171
Graham Swamp, Florida033711170
Northeast and eastern Canada
Port Jervis Watershed Trails, New York031615268
Franconia Area Trails, New Hampshire1825252070
Bromont, montagne d'expériences, Quebec4242122285
Mont-Sainte-Anne, Quebec02151921110
Crabbe Mountain, New Brunswick0244162382
Mountain Bike Minto, New Brunswick0272173343

How the replay worked

  1. We chose 24 riding areas spread across the United States and Canada. Each one had the soil and terrain information Loam needs.
  2. We downloaded the old hourly weather for each place, including rain, snow, temperature, and moisture in the soil.
  3. We ran today's Loam model once a day from January 1 through December 31.
  4. We checked that every hour and every daily result was present before using the numbers.

Altogether, the model read 217,152 hours of weather and produced all 8,760 daily results we expected.

What we can learn from this

This report shows how today's Loam model responds to one year of old weather. Clear patterns appear, including dry summers in the Southwest and long snowy stretches in eastern Canada.

Accuracy is a separate question. We do not have a matching diary of what the trails actually felt like on each day, and the replay does not include old park closures. These 24 places are also a sample, not every riding area in Loam.

Checking accuracy would require dated reports from people at the trails. We could then compare each report with what Loam said on the same day.

The science behind the estimate

Loam starts with a simple physical fact: a trail does not dry just because the rain stops. Water has to enter the ground, move through or across the soil, and leave the trail environment. How quickly that happens depends on the soil, terrain, vegetation, recent weather, and how wet the ground already was.

Soil controls infiltration

Soils do not accept water at the same rate. USDA hydrologic soil groups range from high-infiltration soils such as deep sands and gravels to very slow-infiltration soils associated with clay, high water tables, or restrictive layers. Typical infiltration-rate ranges used in the hydrologic-group framework run from more than 0.30 in/hr for Group A to less than 0.05 in/hr for Group D when thoroughly wet.

Previous rain still matters

A storm does not start with an empty soil profile. USGS notes that soil already saturated from previous rainfall cannot absorb much more, so a larger share of the next storm becomes runoff. Recent weather therefore matters even when the latest storm was not especially large.

Terrain changes the water path

Slope changes how quickly water can move away from a surface. Low spots, drainage features, and trail geometry can change where water collects or leaves the tread. Soil classification and slope are separate pieces of the landscape, which is why both matter to a trail-condition model.

Drying is a water budget

After rainfall, water can remain in the soil, move downward or sideways, run off, or return to the atmosphere through evaporation and plant transpiration. Soil-water-balance models use these processes to estimate changing soil moisture and net infiltration over time.

Why Loam is not a rain timer

There is no useful rule that says every trail becomes rideable after the same number of dry hours. Starting moisture, infiltration behavior, terrain, canopy, and weather after the storm all change the answer.

That is the problem Loam is designed to estimate. The model combines public soil and terrain information with recent weather and network characteristics to estimate how conditions are changing. It is a model of likely trail conditions, not a sensor embedded in the dirt, and it never overrides an official closure.

What the research says

USDA and USGS hydrology work treats infiltration, soil moisture, runoff, canopy, land cover, slope, and evapotranspiration as interacting parts of the water cycle. Recent trail research adds an important piece: rainfall intensity and accumulated rainfall can strongly affect runoff and sediment generation on recreational trails, while wet conditions make trail surfaces more vulnerable to degradation.

USDA NRCS: Hydrologic Soil Groups

Soils are classified by infiltration and runoff behavior when thoroughly wet. The framework distinguishes four main groups and dual drained/undrained classes.

NRCS National Engineering Handbook →

USGS: Infiltration and the Water Cycle

Explains how soil characteristics, saturation, land cover, slope, and evapotranspiration affect where precipitation goes.

USGS Water Science School →

USGS: Soil-Water-Balance

A published water-budget model that estimates soil moisture, net infiltration, evapotranspiration, and canopy interception from gridded environmental data.

USGS SWB Version 2.0 →

NRCS: RUSLE2

A USDA model for estimating soil loss caused by rainfall and associated overland flow, connecting rainfall and runoff to erosion risk.

USDA NRCS RUSLE2 →

Fang & Ng, Journal of Environmental Management, 2026

A year-long field study found cumulative rainfall and maximum daily rainfall predicted runoff and sediment yield on recreational trails, with maximum daily rainfall the stronger predictor in that study.

Read the research →

These sources describe the physical processes and research Loam draws from. They do not describe Loam's proprietary model or disclose its weights and thresholds.