I'm not sure what this has to do with weather in NZ; however, when I run the example, it shows conservation of momentum. The display is a little confusing.

For e=1 (perfect elasticity)
Before:
Ma = 3 Kg Va=2ms­ˉ¹
Mb = 1 Kg Vb=0msˉ¹

Total momentum before = 6 Kgms­ˉ¹

After:
Ma = 3 Kg Va=1ms­ˉ¹
Mb = 1 Kg Vb=3msˉ¹

Total momentum after = 6 Kgms­ˉ¹

From the given web page
http://www.splung.com/content/sid/2/page/momentum)

" * An elastic collision is a collision where the both the momentum and the kinetic energy are conserved."

" * In an inelastic collision the momentum is conserved but the kinetic energy is not. In fact the kinetic energy will be lower after the collision because some energy has been used in creating sound, deformation and heat. The reality is that most collisions are inelastic to some extent. However, collisions between snooker balls come quite close to being elastic collisions."