What is a Risk Burndown Chart?
A risk burndown chart plots total risk exposure (sum of probability × impact across the register) over time — the risk profile's trend line. Healthy projects burn risk down as responses land and uncertainty resolves; a flat or rising line while the schedule advances is a project consuming its future margin.
Agile teams track it per iteration alongside the sprint burndown: one chart says "are we finishing work?", the other says "are we retiring uncertainty?" — and the second predicts the first.
Formula
Exposure = Σ(probability × impact) across open risks, plotted per period
Worked example
A platform migration's burndown starts at $4.2M exposure. Sprints 1–6 retire the big unknowns — data-mapping spike, performance proof, vendor API contract — and the line falls to $1.1M. In sprint 9 it jumps $800K: a compliance interpretation went sideways. The chart makes the jump impossible to ignore in the steering pack, and the response gets resourced that week, not at the quarterly review.