Replacement stuff and Periodization

Hi,

If a program calls for 5x5H or 4x8- 12H BUT when is raining you cant do it because the track basically becomes mud(non-tartan, old school track) BUT you have a 35m indoor facility where you can set up 2 hurdles at standard distance. What do you do?

Or if you have to do 50- 60m sprints but again, its raining, you need get inside the 35m facility, what do you do?

Or what if you need to do 2- 3x300m or 3- 4x200 or 2x4x80+300m, what do you do instead in a 35m long facility?

I saw one of Angela’s tweet about ‘‘periodization is dead’’ … what does that mean?

Thank you