February lottery for Wonderland Trail and climbing-route reservation windows, then the late-April general on-sale.
"Because demand for trips on the Wonderland Trail and high-use climbing routes exceeds capacity during peak periods, an optional early-access lottery is available." It "opens in February each year"; winners get an individual access window "between March and April", and "general reservations open" after "April 25, when the early access window closes". "Approximately one third of campsites are not reservable in advance". Confirmed on https://www.nps.gov/mora/planyourvisit/wilderness-permit.htm. The February lottery and the general on-sale after April 25 are the scarcity moments this target watches for.
Updated , checked by hand against the target's own page.
Watched from nps.gov, the target's own public page — not a reservation system we poll.