Crash momentum
Marks bars where price has dipped over the lookback window; the crash-strength checks cannot fire on this chart.
CrashMomentum adds three checks and returns their total, from 0.3 to 1.0, when it is above zero. It adds 0.3 when roc_fast is below -0.01, 0.3 when roc_fast minus roc_slow is below -0.005, and 0.4 when roc_fast has fallen by more than 0.01 across the lookback window. The indicator was written for rate-of-change inputs, but on this chart both inputs are wired to the raw close, so the first two checks never pass and only the window-drop check scores, always 0.4.
How to read it
- Markers sit on the candles where the output is on. At default settings that is about half of all bars, so the chart is dense with markers.
- A marker means the close is more than one cent below its level lookback minus one bars earlier. A run of markers on consecutive candles is a steady slide; a lone marker is a small dip.
- Every marker carries the same strength, 0.4, so the markers do not show how hard price fell.
- Treat a marker as a small net decline, not a crash signal, despite the name.
What it outputs
- Crash strength
- Sum of the three checks, 0.3 to 1.0 when on. On this chart it is always 0.4, the window-drop check alone, so markers show where that check passes.
When it fires
Fires when the close is more than one cent below its level lookback minus one bars earlier, the only check that passes on this chart. That moment is a small net decline over the window, not an accelerating crash.
Settings
- lookback
- Bars the price change is measured over; the first lookback minus 1 bars stay empty. Shorter (3 to 5) flickers more on brief dips; longer (30 or more) needs a sustained slide and tends to switch less. At 1 it never fires on this chart.
Pitfalls
- roc_fast and roc_slow have no default, so this chart wires both to the raw close; the level and acceleration checks cannot pass because close minus close is zero.
- Not rare: in the September 2026 SPY sample it was on for 47% of one-minute bars, about 78 switch-ons a day, so markers are dense and do not flag crashes.
- The -0.01 threshold is in input units. On raw price it is one cent, not a 1% move, so the check does not measure how large a drop is.