Not exactly impossible but Inessa Kravets' WR turned 25 years old yesterday.
What people don't remember is she had two no jump and this was basically a "safety" effort as she took off very early on the boards. This was a 15,6X effort tbh.
For a while there was a bunch of 15,3X results in women's triple jump but still nobody has broken this one.
Btw, Kravets' 1996 Olympic gold jump (15,33 into a head-wind) is still 6th on the all-time list as well.