‘Avalanche!’ – A word we don’t want to hear you say

By Dr. Michelle Windle
Many farms have a limited amount of space on the feed pad to store their homegrown forages.  This leads some producers to store multiple crops in close proximity.  For example, a farm may put freshly chopped corn on top of already-fermented haylage.  More commonly, farms have carryover from the previous year at the time a new crop is harvested, and limited pad space, so they’ll clean the face of the old feed and begin filling with the new crop against it.

January and February mark the time of year when many producers move from one crop to another.  Although avalanches can occur in a wide array of situations, it is especially common to see an avalanche at the interface between two crops.  This creates a dangerous situation.

Among other potential factors, differences in shrink rates and uneven densities can cause forages to shift.  When crops are piled one on top of another, the bottom (already ensiled) crop is uncovered and re-exposed to oxygen, which can cause spoilage.  After the new crop is piled on top, packed, and sealed, the bottom crop undergoes a secondary fermentation, which is accompanied by the standard spoilage and fermentation shrink, and the crop shifts.  The top crop now sits on unstable ground, which makes it prone to avalanches.

When two crops are adjacent to each other, the seam is especially prone to avalanches.  Although the crops start even with each other once packed and sealed, the newer, unfermented crop goes through fermentation shrink and shifts, causing an unstable interface between the two crops.  This is what most likely causes an avalanche when switching from one crop to another.

One misconception is that making a ramp will help prevent avalanches.

In a recent Hay & Forage Grower^® article, Chris Wacek-Driver, Forage Innovations, LLC, commented, “Operators have tried to minimize the risk of avalanching by facing the older forage at a 45-degree angle prior to bringing in the new forage.  Usually, this simply prolongs the area susceptible to avalanching.”

Click here to access the article for further discussion on the topic.

Our best advice is to store different crops separately.  It’s the safest option.

Here are a few other safety reminders as you work with and around forage piles and bunkers:

1. If you don’t need to be near the face of a bunker – don’t be there!
2. Wear high-visibility clothing if you are working near a bunker or pile.This prevents accidents by making you easier to see.  It may also aid emergency response efforts in the event of an accident.
3. If the pile exceeds 12 feet in height, never approach the face alone.  Always have another person in the area, but stationed away from you and the silage face.  This support person should watch the face of the silage for any indication of a problem and give warnings about any movement of the silage whatsoever.
4. Never approach the silage face if it has an overhang or frozen chunks or tires sitting at the top of the pile.  A properly maintained silage face still poses a risk, but these situations are especially dangerous.
5. Work with extreme caution if you are on top of the pile.  This is an exposure-to-fall hazard.  If you need to be on top of the pile, stay away from the feeding face or sides of the bunker.  Remember that plastic is very slippery, especially in the winter.

About the author:  Dr. Michelle Windle is a Vita Plus forage products and dairy technical service specialist. Windle earned her bachelor’s and master’s degrees in animal science at the University of Delaware. She continued there to earn her Ph.D. in animal and food science, specializing in forage research with Dr. Limin Kung. Her thesis research centered on the use of a protease to improve starch digestibility earlier in the ensiling process. A New Jersey native, Windle gained much of her farm experience during her collegiate years, milking cows, working in a forage laboratory, and performing dairy research. Based in Madison, Wisconsin, Windle’s responsibilities at Vita Plus include forage product research and development, dairy research, and dairy technical services.