Snubber circuit is used to protect SCR from $d_v/d_t$ turn ON.

A snubber circuit consists of a series combination of resistance $R_s$ and capacitance $C_s$ in parallel with the thyristor as shown in figure.

When forward voltage is applied across the thyristor capacitor $C_s$ charges slowly and prevents sudden rises of voltage across the thyristor.

The purpose of connecting resistor $R_s$ in series with $C_s$ because, When thyristor turn ON,Capacitor discharges through thyristor and sends a heavy current and may damage the thyristor.

In order to limit the discharge current a resistance $R_s$ is connected in series with $e_s$.