snowball effect

What it means

A snowball effect is when a small action or event triggers a process that grows steadily in size, importance, or speed. It's used in finance (compound interest), social media (viral posts), debt (mounting balances), and politics — anywhere a tiny push leads to outsized results over time.

Examples

• One viral post had a snowball effect on her follower count.
• Skipping payments creates a snowball effect with credit-card debt.
• Small acts of kindness can have a real snowball effect in a community.
• The product launch had a snowball effect across the whole industry.

Where it comes from

From the 19th-century image of a small snowball rolling downhill, gathering more snow and growing larger as it goes. The metaphorical use for self-reinforcing growth was common in English by the late 1800s.

Related idioms