Why this might be first sign of reversal
The Relative Strength Index is often used to determine current conditions on the market and point out reversal points once the price reaches oversold or overbought values.
The indicator is also used to find divergences against the price chart and then determine whether the trend on the asset is reversing.
But while divergences could be considered an additional way of using the indicator, looking for oversold and overbought levels is the main way of using the Relative Strength Index.
While the RSI can give us a hint about the upcoming movement in the future, it is not a panacea against the bear trend since its signals are usually considered short term. Almost every reversal signal based on RSI stays active until the indicator's values enter the "neutral" zone.