What changed in v0.4
BeachCut now reports two separate tide-access scores for every forecast low.
4-week score = percentile of the forecast low against low tides from the previous 28 days. A score of 100 means it is lower than every low tide seen in that recent baseline.
Historical score = comparison with a fixed long-term tidal reference stored inside this file. It does not make a multi-year web request. The reference is anchored to published ADMIRALTY Mean Low Water Neaps (MLWN) and Mean Low Water Springs (MLWS) for the nearest suitable standard port, with a fixed spring–neap distribution shape. The current model datum is aligned to that reference from the previous 28 days of low waters before scoring.
This is intended to answer the more important question: “Is this genuinely a deep low in the context of the local tidal regime, rather than merely the lowest tide this month?”
The combined Tide Access value used by the Detecting Opportunity score is 70% historical + 30% 4-week. The long-term reference is embedded, so it is always available offline once the normal forecast has loaded.
4-week score = percentile of the forecast low against low tides from the previous 28 days. A score of 100 means it is lower than every low tide seen in that recent baseline.
Historical score = comparison with a fixed long-term tidal reference stored inside this file. It does not make a multi-year web request. The reference is anchored to published ADMIRALTY Mean Low Water Neaps (MLWN) and Mean Low Water Springs (MLWS) for the nearest suitable standard port, with a fixed spring–neap distribution shape. The current model datum is aligned to that reference from the previous 28 days of low waters before scoring.
This is intended to answer the more important question: “Is this genuinely a deep low in the context of the local tidal regime, rather than merely the lowest tide this month?”
The combined Tide Access value used by the Detecting Opportunity score is 70% historical + 30% 4-week. The long-term reference is embedded, so it is always available offline once the normal forecast has loaded.
0–29 low
30–54 watch
55–74 high
75–100 exceptional
How to use the window
Each recommended window is tied to a specific low tide. The default plan is:
arrive 2 hours before low water → follow the ebb out → reach the lowest exposed strip around low water → continue for about 1 hour as the flood begins.
On very flat beaches the app deliberately values the extreme low because the most seaward ground may only be practically searchable for tens of minutes.
The “Where to focus” line changes with the mechanism. After erosion it prioritises cuts, troughs, shell/gravel and heavy-target lines. During an extreme low without much erosion it prioritises the seaward continuation of the busiest bathing/access corridor, especially channel edges and the furthest normally submerged strip. Formby remains monitoring-only because National Trust currently states that recreational detecting is not permitted on its managed land.
The “Where to focus” line changes with the mechanism. After erosion it prioritises cuts, troughs, shell/gravel and heavy-target lines. During an extreme low without much erosion it prioritises the seaward continuation of the busiest bathing/access corridor, especially channel edges and the furthest normally submerged strip. Formby remains monitoring-only because National Trust currently states that recreational detecting is not permitted on its managed land.