\begin{tabular}{|l|l|l|l|l|l|}
\hline
\multicolumn{5}{|c|}{Konsekvens} \\
\hline
& & Liten & Middels & Kritisk & Katastrofal \\
 \hline
\begin{sideways}Sannsynlighet\end{sideways}
& Lite sannsynling & \cellcolor{green} & \cellcolor{yellow} & \cellcolor{yellow} & \cellcolor{red} \\
& Sannsynlig & \cellcolor{green} & \cellcolor{yellow} & \cellcolor{yellow} & \cellcolor{red} \\
& Meget sannsynlig & \cellcolor{yellow} & \cellcolor{yellow} & \cellcolor{red} & \cellcolor{red} \\
& Svært sannsynlig & \cellcolor{yellow} & \cellcolor{red} & \cellcolor{red} & \cellcolor{red} \\
\end{tabular}