An avalanche made up of ice which the ice becomes snow
What she means is that she had made 19 trips to Maryland, helped 300 people to freedom, yet she was never captured and didn’t fail to deliver her "passengers" to safety. As Tubman herself said, "On my Underground Railroad I [never] run my train off [the] track [and] I never [lost] a passenger." During these journeys she helped rescue people that were from her own family and people who weren’t from her own family. You can check her story in the America Library.
As a responsible citizen she should eat the dead fish <3
Spring would be the most inappropriate.
Spring is commonly used in literature to represent things like birth, new beginnings, growth, etc. Overall, Spring is used to show positive themes. To best represent a nearing death and other negative themes, an author should opt to use Winter or Autumn.