Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_1241987_1 (year INTEGER, regular_season VARCHAR)

### Question ###
What is the lowest year that regular season is 4th, Rocky Mountain?

### Accurate SQL ###

SELECT MIN(year) FROM table_1241987_1 WHERE regular_season = "4th, Rocky Mountain"