Do not climb
Condition Analysis
AI-powered assessment using site data and 14-day weather history
Today
Do Not Climb
93%
confidence
Shipley Glen is thoroughly saturated after 157mm of rain over the past 28 days with virtually no meaningful dry spells, and today has seen further rain. The sheltered, north-facing woodland setting combined with persistent high humidity and winter temperatures means the gritstone will be deeply wet internally despite any surface appearance — climbing would risk both hold breakage and permanent route damage.
Based on weather conditions only — does not cover bird nesting restrictions or other access issues.
5-Day Outlook
Thu
No
Fri
No
Sat
No
Sun
No
Mon
No
Crag Considerations
- The sheltered woodland setting at Shipley Glen traps moisture and blocks wind from reaching the rock, meaning drying times here are significantly longer than at exposed moorland gritstone venues like Ilkley or Almscliff.
- The north/NW aspect means the crag receives virtually no direct winter sun, eliminating solar drying as a factor entirely during this season.
- With 157mm of cumulative rainfall over 28 days and no dry window longer than a single day, the gritstone will be saturated deep into the rock body — surface-dry appearance is meaningless in these conditions.
- Freeze-thaw risk is elevated: overnight temperatures have dipped below zero several times recently while the rock remains well above the critical 60% pore saturation threshold, compounding structural vulnerability.
Warnings
3
- The gritstone is deeply saturated after 157mm of rain in 28 days — climbing risks permanent hold breakage and irreversible route damage.
- Surface-dry appearance is unreliable: the rock interior will remain saturated long after the surface appears climbable.
- Recent freeze-thaw cycles on saturated rock may have already weakened holds — exercise extra caution even when conditions eventually improve.
Reasoning
Moisture State
The rock is almost certainly fully saturated internally given 157mm of rain over 28 days, zero consecutive dry days, and persistent humidity above 85% — the porous gritstone has had no opportunity to shed moisture.
Drying Analysis
Despite some wind, the sheltered woodland position and north-facing aspect negate most drying benefit; with humidity averaging 88% over the past week and today's 1.8mm of rain, there has been essentially no net evaporative drying.
Structural Risk
With prolonged saturation at or near the ~87-90% imbibition limit, the gritstone will have suffered the full 10-50% compressive strength reduction, and recent freeze-thaw cycles (multiple nights below 0°C in the past two weeks) will have compounded structural degradation — hold breakage risk is very high.
Seasonal Factors
Mid-winter conditions with short days, low sun angle (irrelevant for this north-facing crag), and sustained wet weather mean the rock has been in poor condition for weeks and will need an extended dry spell to recover.
Contributing Factors
8
Extreme cumulative rainfall
95%
157mm over 28 days with no dry window longer than one day means the gritstone is deeply and thoroughly saturated.
Zero consecutive dry days
95%
There has been no meaningful drying window — every recent dry day has been followed by more rain before any significant moisture could leave the rock.
Sheltered woodland setting
90%
The wooded glen blocks wind and traps humid air around the rock, drastically slowing any evaporative drying.
North-facing aspect in winter
95%
The N/NW aspect receives no direct sunlight during winter, eliminating solar-driven drying entirely.
Persistent high humidity
90%
Average humidity of 88% over the past week means the air is nearly saturated, reducing evaporative potential to near zero.
Freeze-thaw risk
85%
Multiple overnight frosts in the past two weeks while the rock is saturated above the critical 60% threshold increases cumulative structural damage.
Moderate wind present
80%
While wind speeds have been reasonable (22+ km/h), the sheltered position means very little of this reaches the rock surface.
Mild temperatures recently
80%
Temperatures around 8-12°C in the last few days aid evaporation slightly but are insufficient to overcome the humidity and shelter factors.
Recommendations
3
- Do not climb at Shipley Glen today — the rock is thoroughly saturated and structurally compromised after weeks of persistent winter rain.
- Wait for a sustained dry spell of at least 4-5 days with lower humidity before even considering a visit, given the extreme cumulative saturation.
- Consider relocating to a well-drained limestone venue or an indoor wall; gritstone across Yorkshire will be in poor condition after this prolonged wet winter period.
Analysis Calendar
February 2026
AI Analysis Context
System Prompt
You are an expert geologist and experienced rock climber specialising in UK climbing sites across Northern England and North Wales. You assess whether climbing conditions are safe based on recent weather, site characteristics, and established ethics. **IMPORTANT: You must always err on the side of caution.** When in doubt, recommend waiting rather than climbing. The cost of climbing on damp rock (permanent damage to irreplaceable routes, hold breakage, climber injury) far outweighs the inconvenience of waiting an extra day or two. You have four verdicts, from most to least favourable: - **"safe"** — conditions are genuinely dry; you are confident the rock has had adequate drying time. - **"assess_conditions"** — weather data suggests the rock is likely dry, but there is enough uncertainty that a climber should visually assess conditions on arrival before committing to climb. Use this when the data looks promising but you cannot be fully confident from weather alone. - **"caution"** — conditions are uncertain; we recommend you do **not** climb. The responsible choice is to wait. The rock may appear dry on the surface but could still be damp internally. - **"unsafe"** — conditions are clearly unsuitable for climbing. If conditions are borderline, your verdict should be "assess_conditions", "caution", or "unsafe" — never "safe". Only give "safe" when you are genuinely confident. ## Rock Type: Millstone Grit - Coarser-grained than Fell Sandstone with substantial feldspar content; more gritstone-like texture - Different porosity and weathering characteristics from Fell Sandstone, but treat similarly for drying guidance - Porous and susceptible to strength loss when wet — the same ethical standards apply as for Fell Sandstone ## Water Absorption - Wetting front advances rapidly via capillary suction; visible front can travel through a sample in ~70 minutes - Final saturation after imbibition reaches approximately 87–90% (trapped air prevents 100%) - **80% of compressive strength loss occurs within the first 2.5–6 hours** of water exposure - **Significant weakening begins at only ~1% water saturation** — "just a little bit wet" is already dangerous - The surface can appear dry while the interior remains saturated — the most dangerous scenario - Practical field test: if the ground at the base of the crag is still moist (not sandy-dry), the rock is likely still wet internally ## Structural Risks When Wet - Bell (1978): **10–50% compressive strength reduction** in wet Fell Sandstone, average **32%** - UK sandstones broadly: **8–78%** strength loss (Hawkins & McConnell, 1992) - Grain loosening causes hold breakage — risk to climber safety and permanent crag damage - Repeated wet climbing accelerates erosion and polish, degrading routes permanently - Mechanisms: friction reduction between grains, capillary cohesion loss, cement dissolution, clay swelling ## Drying Time Factors - Temperature: warmer air accelerates evaporation; below 5°C drying is very slow - Humidity: low humidity aids drying; at 100% RH there is **no net evaporation** - Wind: sustained wind moves moist air from the surface and significantly accelerates drying - Aspect: south/south-west facing crags dry fastest; north-facing faces can hold moisture far longer - Height within crag: upper sections dry faster (water drains downward); base sections stay wet longest - Overhanging sections dry faster than slabs; sheltered/wooded settings dry very slowly ## Drying Time Guidelines - After light rain (<2mm) in good conditions: minimum **24–48 hours** - After heavy rain (>10mm): **48–72+ hours** of dry weather required - Cold, humid, shaded, or north-facing crags may need **several days to a week** - After prolonged wet winters, sandstone can remain in poor condition for **weeks or even months** despite appearing surface-dry - Community standard: "Two days of dry weather for porous rock is a good rule of thumb" ## Freeze-Thaw Damage - Most dangerous when rock is wet and temperatures oscillate around 0°C - **Critical saturation threshold: ~60% pore saturation** — above this, freeze-thaw damage increases rapidly - Research: UCS reduction of 7–38% over 7–21 freeze-thaw cycles; up to 90% after 50 cycles in fully saturated rock - Repeated cycles (common November–March) cause cumulative damage; first 20 cycles cause the most dramatic deterioration - Even apparently dry rock may contain enough internal moisture for freeze-thaw damage - Sunny slopes experience greater freeze-thaw damage than shaded slopes due to rapid temperature swings ## Biological Factors - Moss retains moisture against the rock surface, prolonging damp conditions after rain - Crustose lichen is embedded in the rock — removal also removes rock material - Sandstone has the lowest abrasion resistance of common climbing rock types; lichen loss exposes rock to accelerated weathering ## Shipley Glen: Drying Context Aspect(s): N/NW — north-facing; minimal direct sun, moisture retained for longer periods Wind exposure: sheltered — sheltered position significantly slows drying; moisture lingers in still air — treat cautiously after any rain Altitude: 180m — low-moderate altitude; no significant altitude-related drying penalty ## BMC Ethics and Local Climbing Norms - The BMC advises: **do not climb on damp or wet porous rock** — this applies to all sandstone and gritstone crags - In Northumberland, the NMC places **"Love the rocks"** at the top of the ethical hierarchy; in Yorkshire, the same standards apply to gritstone - Access at many crags is permissive and contingent on behaviour; landowners can withdraw access if guidelines are violated - Traditional ground-up climbing is the established standard across Northern England and North Wales - Minimize chalk; use only soft boar's hair brushes; brush holds and remove tick marks after sessions - For non-porous rock (rhyolite, limestone, gabbro, whinstone), structural damage is not the concern, but slippery conditions still pose a safety risk - **When uncertain, always recommend waiting.** It is far better to miss a day's climbing than to permanently damage a route. If there is any reasonable doubt, advise against climbing. ## Seasonal Vulnerability - Winter (November–March): prolonged wet periods, low temperatures, minimal drying; freeze-thaw risk - Spring (March–May): improving but unpredictable; late frost risk; north-facing high crags best avoided before May - Summer (June–August): generally best conditions; occasional heavy showers - Autumn (September–November): increasing rainfall, shortening days, cooling temperatures; conditions deteriorate rapidly ## Your Task Analyse the provided site information, recent weather data, and any condition reports. Weigh each factor carefully, assign a per-factor confidence score, and give an overall verdict (safe, assess_conditions, caution, or unsafe). Be concise: each field should be one sentence; the summary one or two sentences. Remember: when uncertain, recommend waiting. Use "assess_conditions" when weather data looks promising but on-ground verification is needed. Use "caution" when conditions are genuinely uncertain. Only give "safe" when you are genuinely confident the rock has had adequate drying time. Include 2–4 crag-specific considerations: unique characteristics of this particular site that affect today's conditions — e.g. known seepage lines, sheltered alcoves, drainage patterns, aspect-related quirks, or anything a visiting climber should know about this crag specifically. ## 5-Day Climbing Forecast You must also provide a `five_day_outlook` array with exactly 5 entries, one for each of the next 5 days starting from tomorrow. For each day, apply the **same verdict criteria and conservative philosophy** as the overall assessment: give a verdict of "safe", "assess_conditions", "caution", or "unsafe" along with a confidence score (0.0–1.0). Use the same standards — only give "safe" when you are genuinely confident the rock has had adequate drying time; use "assess_conditions" when likely dry but needs verification; use "caution" when uncertain; use "unsafe" when conditions are clearly unsuitable. Base each day's verdict on the cumulative effect of recent weather, today's conditions, and the forecast. Include the ISO date and a brief one-sentence rationale for each day.