Tornado Day Percentage:
22.73% ⓘTornado Days divided by Convective Chase Days — the share of convective chase days that produced at least one witnessed tornado.
Tornadoes per Mile:
0.0008 ⓘTotal tornadoes witnessed divided by total miles driven — a rough measure of chasing efficiency. Higher means more tornadoes for the driving effort.
Average Miles per Tornado:
1,250.5 ⓘTotal miles driven divided by total tornadoes witnessed — the same ratio as Tornadoes per Mile, just flipped into "miles per tornado" instead of "tornadoes per mile."
Busts: 9 ⓘA "Bust" day: storms were expected and something did fire, but the setup underperformed the forecast — a weaker, shorter-lived, or less organized event than anticipated.
Blue Sky Busts: 0 ⓘA "Blue Sky Bust" day: nothing fired at all — clear skies despite a forecast that called for storms.
Kiss of Death Days:3 (2–1)ⓘA "Kiss of Death" day: the SPC tornado outlook included a 15% hatched (significant) tornado probability within a Slight, Enhanced, or Moderate risk (Categorical Risk 1–3) — a favorable-looking setup that historically often underperforms relative to the risk level. Shown as days chased (with tornadoes–without).
SPC Risk Record:ⓘThe SPC Day 1 outlook risk where the chase actually was (states chased, within 200 miles of the GPS track when there is one) — not the highest risk anywhere in the country that day. Based on 22 of 22 convective chase days with a known risk (chases outside the US are left out).
Tornadoes by SPC Tornado Risk:ⓘThe SPC tornado probability right at each tornado's location, from the Day 1 outlook in effect when it happened. When no time was logged, it's estimated from the GPS track, or else assumed to be late afternoon (0 of 8 tornadoes). 0% means the spot was outside even the 2% area.
1.00″ 
2
1 
80 mph 
Chase Statistics for 2013