Slots with the Avalanche (cascading) mechanic explained

Added: May 25, 2022

Last updated: April 23, 2023

More and more online slots make use of the avalanche feature

We see that the Avalanche mechanic (or Avalanche feature) has become increasingly popular since 2016-2017. This mechanic is also called the Cascading mechanic or Tumbling symbols mechanic.

The idea is simple. If you win, you gain a free re-spin, and the winning symbols disappear and make way for new symbols. This combination is called a reaction. This way,  you get a new chance to make another win.

If you win again, you gain another free re-spin, which continues until you fail to make a new win.

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In some exceptional cases (e.g. Play’n GO’s Black Mamba), no new symbols appear, and therefore the number of symbols on the grid decreases with the re-spin.

This feature is prevalent, as it offers so many more possibilities for game studios to vary the gameplay.

Most Megaways slots and grid slots make use of this mechanic, and these slots have become incredibly popular over the past couple of years. Experienced slot players seek more challenging slots, and this feature helps!

Netent’s famous Gonzo’s Quest slot (below we show it) was the first to introduce this powerful mechanism. Nowadays, you can ask yourself why they didn’t trademark this feature!

Explanation of the steps of a reaction

Below we illustrate the four steps for a Megaways slot.

Step 1: it starts with a win

The Avalanche mechanic starts once you have a win, as illustrated below. The green symbols on reels 1 to 4 make a winning combination. The green symbols of reel 6 are not part of the win, as there are no green symbols on reel 5.  

Step 2: the winning symbols disappear, and the remaining symbols drop (tumble)

You see that the green winning symbols on reels 1 to 4 are destroyed and disappear afterwards. This way, empty positions appear, and as a result, the remaining symbols (that were non-winning) drop or tumble downwards. These symbols are called the tumbling symbols or the dropping symbols.

In this example, no symbols drop on reel 4, as no symbols are left on reel 4 (both were winning).

Step 3: empty positions on top of the reels

Once all symbols have tumbled, you see empty positions on the top of the reels.

Step 4: new symbols appear

Afterwards, new symbols appear, such that the playing field (or grid) is complete with symbols.

You have two new symbols on reels 1, 2 and 4 and one new symbol on reel 3. Nothing changed on reels 5 and 6.

Noteworthy is that the total number of symbols remains constant and that the number of Megaways is still intact.


Next steps

If you get another win (after the new symbols show up), the whole reaction starts all over again.

These reactions (and therefore free re-spins) continue till you fail to make a new win. 

Some examples of the avalanche mechanic

Below we have four examples of this feature for some of the most famous slots.

We start (and rightfully so) with Netent’s Gonzo’s Quest, a classic 5×3 slot with 20 paylines. If you win, you gain a free re-spin, and the total win multiplier increases from x1 to x2 to x3 to eventually x5 (after three successive wins).

Almost all grid slots make use of the cascading feature, and below, you see it illustrated for Play’n GO’s Reactoonz 2.

We finish our examples with Big Time Gaming’s Monopoly Megaways.

Below (by coincidence), you see that all reels have seven symbols, making the maximum of 117,649 Megaways.

 Additional features, thanks to the avalanche mechanic

Besides the re-spins, you have more possibilities. With grid slots, for example, you often see that you gain the free spins after 4 or 5 successive reactions.

With Megaways slots (like Gonzo’s Quest), you benefit from an increasing win multiplier after each re-spin. If you win many consecutive times, you have a high multiplier.


Nowadays, we cannot think of a world without the Avalanche mechanic!

The number of possibilities is tremendous, and it’s for the reason that Megaways slots and grid slots thankfully make use of this feature.

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