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Discovery Farms · SW Colorado

Drought Conditions
& Landscape Change

An exploration of drought severity, vegetation response, and water availability across SW Colorado's agricultural watersheds — from 1984 to present. Produced in collaboration with Discovery Farms, an agricultural research organization with sites in Grand Valley and SW Colorado.

Drought Conditions

Year-by-Year Drought Conditions

Step through peak-summer (August) drought conditions across SW Colorado from 2000 to present. Drag the slider or use arrow keys to explore how drought severity has varied year to year.

August 2000 — USDM peak drought classification

2000 2025 2000
D0 Abnormally Dry D1 Moderate D2 Severe D3 Extreme D4 Exceptional

Landscape Change

Seeing Change from Space

Annual peak-season satellite imagery reveals how the landscape has responded to drought cycles over four decades. False color and natural color composites are shown side by side — false color uses SWIR/NIR/Red to emphasize vegetation health and moisture stress, while natural color provides a familiar reference view. Below, a higher-resolution Sentinel-2 closeup shows Grand Valley in detail.

Landsat false color time series — SW Colorado 1984–present

False color (SWIR/NIR/Red) — highlights vegetation health and moisture stress. Green indicates healthy vegetation; brown indicates stress or bare soil.

Landsat natural color time series — SW Colorado 1984–present

Natural color (Red/Green/Blue) — true-color view of the same region and time period for comparison.

Sentinel-2 false color time series — Grand Valley 2017–present

Grand Valley closeup — Sentinel-2 at 10m resolution, 2017–present. Shows irrigation patterns and crop-level moisture stress.

Drought Trends

How Has Drought Changed Over Time?

Two complementary views of drought history across the SW Colorado region — a long-term moisture index spanning nearly seven decades, and a modern record of severe drought frequency since 2000.

Annual Mean PDSI — SW Colorado 1958–present

Palmer Drought Severity Index (PDSI) — annual mean across SW Colorado, 1958–present. Negative values indicate drier than average conditions.

Severe Drought Extent — SW Colorado 2000–present

Percentage of SW Colorado in D2 (Severe) or worse drought each August, 2000–present.

Methods

Data & Approach

All analysis was conducted using Google Earth Engine and Python. Data sources and methods are summarized below.

Data Sources & Methods

  • USDM drought maps — weekly classifications, D0–D4, 2000–present (NDMC/NOAA/USDA)
  • TerraClimate PDSI — monthly Palmer Drought Severity Index, 1958–present (~4km)
  • Landsat 5/7/8/9 — harmonized false color and natural color composites, June–October, 1984–present (30m)
  • Sentinel-2 SR — false color composites, July–August, 2017–present (10m)
  • Region: Delta, Dolores, Gunnison, La Plata, Mesa, Montezuma, Montrose, Ouray, San Miguel Counties
  • Cloud masking via per-pixel QA band; gap fill using 25th percentile fallback
  • Trend lines computed via ordinary least squares linear regression