10. The Government may incur overruns for more than one fiscal year if it anticipates, in a Budget Speech and prior to the implementation of an offsetting financial plan, an overrun of $1,000,000,000 or more in the fiscal year covered by the budget, or if an overrun of $1,000,000,000 or more is recorded for a fiscal year, as a result of
(1) a disaster having a major impact on revenue or expenditure;
(2) a significant deterioration of economic conditions; or
(3) a change in federal programs of transfer payments to the provinces that would substantially reduce transfer payments to the Government.